NIST–JANAF Thermochemical Tables for the Bromine Oxides

Cite as: Journal of Physical and Chemical Reference Data 25, 1069 (1996); https:// doi.org/10.1063/1.555993 Submitted: 25 July 1995 . Published Online: 15 October 2009

M. W. Chase

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© 1996 American Institute of Physics for the National Institute of Standards and Technology. NIST -JANAF Thermochemical Tables for the Bromine Oxides

Malcolm W. Chase Standard Reference Data Program, National Institute of Standards and Technology, Gaithersburg, Maryland 20899

Received July 25, 1995; revised manuscript received May I, 1996

The thermodynamic and spectroscopic properties of the bromine. oxide species have been reviewed. Recommended NIST -JANAF Thermochemical Tables are given for six gaseous bromine oxides: BrO, OBrO, BrOO, BrOBr, BrBrO, and Br03' Sufficient information is not available to generate thermochemical tables for any condensed phase species. Annotated bibliographies (over 280 references) are provided for all neutral bromine oxides which have been reported in the literature. There are needs for additional experimental and theoretical data to reduce the uncertainties in the recommended values for these six species. Of all the species mentioned in the literature, many have not been isolated and characterized. In fact some do not exist. Throughout this paper, uncertainties attached to recommended values correspond to the uncertainty interval, equal to twice the standard deviation of the mean. © 1996 American Institute of Physics and American Chemical Society. Key words: bromine oxides; evaluated/recommended data; literature survey; spectroscopic properties; thermodynamic properties.

Contents 6.2. OBrO(g)...... 1094 1. Introduction...... 1069 6.3. BrOO(g)...... 1095 1.1. References for the Introduction...... 1071 6.4. Br03(g)...... 1096 2. Chemical Species Coverage ...... , 1072 6.5. BrOBr(g)...... 1097 3. Historical Perspective of Bromine Oxide Studies. 1072 6.6. BrBrO(g)...... 1098 4. Summary of the Data for the Bromine Oxide 7. Conclusions...... 1099 Species...... 1073 8. Acknowledgments...... 1099 4.1. Spectroscopic Information...... 1073 9. References-Annotated Bibliographies...... 1100 4.2. Thermodynamic Information...... 1073 5. Discussion of the Literature Data...... , 1073 5.1. BrO...... 1074 List of Tables 5.2. OBrO...... 1079 2.1. Bromine Oxide Species...... 1072 5.3. BrOO...... 1085 5.1.1. KotatlOnal Constants tor 131'0...... l.O75 5.4. Br03 ...... 1085 5.1.2. Rotational.and Electronic State Splitting 5.5. Br04...... 1086 Constants for BrO...... 1077 5.6. BrOBr...... 1086 5L3 Dissociation Energy of BrO...... 1079 5.7. BrBrO...... 1088 6. Bromine Oxide Species: Structure and 5.8. Br2(02)...... 1089 Vibrational Frequencies...... 1081 5.9. Br203...... 1089 7.1. Thermodynamic Properties of the Bromine 5.10. BrOBr02...... 1089 Oxides...... 1099 5.11. 02BrBr02'" ...... 1090 5.12. 02BrOBrO ...... 1090 5.13. BrBr04...... 1090 1. Introduction 5.14. Br20S ...... 1090 5.15. Br206 ...... 1091 5.1fi. Rr207' 1091 As a continuation of previous studies which dealt with the 5.17. Br30g ...... 1091 thermodynamic properties of the chlorine oxides I and oxy­ 6. NIST-JANAF Thermochemical Tables ...... 1092 gen fluorides,2 this study deals with the neutral bromine ox­ 6.1. BrO(g)...... 1093 ides. A succeeding article will deal with iodine oxides. We will Hul lli~CllS~ lhe: aSlatine uxilles, as there appears to be only an estimated D~ value reported in the literature for (i) 1996 by tlw C.S. Secretary of Commerce on behalf of the United States. AtO(g). Specifically, this study examines the thermodynamic All rights resem~d. This copyright is assigned to the American Institute of Phy..;j(,<; :lnd rhi' .... meril'an Ch.?mical Society. properties of the neutral oxides. not the gaseous ionic and Reprint~ available from ACS; see Reprints list at back of issue. aqueous ionic species. The main purpose of this article is to

0047 -2689/96/2S( 4)/1 069/43/S14.00 1069 J. Phys. Chern. Ref. Data, Vol. 25, No.4, 1996 1070 MALCOLM W. CHASE generate thermochemic.al tables for bromine oxide species. Russian counterpart by Glushko and Medvedev6 listed values In generaL there are scant data available for the description (C;,HO, S°, and ~"fHO) at 298.15 K for BrO(g), but only an of the spectroscopic and thermodynamic data for any of the enthalpy of formation for Br02(cr). [The NBS Tables also bromine oxides, except for BrO, OBrO, and BrOBr. Al­ listed values for three aqueous ions, Glushko and Medvedev though the prime emphasis was on the diatomic and tri­ listed two aqueous ions.J It should be noted that the NBS atomic species, a thorough search of all bromine oxygen spe­ study was performed in 1964 and the Russian study in 1965, cies was conducted to decide which species had sufficient and were based on the same references. data. There are many NASA-JPL publications on chemical ki­ For the time period 1907 to 1994, there are only 280 cita­ netics in which enthalpy of formation tables are given. Of all tions in Chemical Abstract Services (CAS) dealing with all the bromine oxides, only BrO(g) is listed by NASA-JPL.7 phases of the bromine oxides; of these 147 deal with BrO, 45 These data are presented without citation or reference to the deal with OBrO. and 25 with BrOBr. Of the approximately original source. Most of the recommendations are based 25 oxides mentioned in the literature, however, there is not upon data in the IUPAC Evaluation (Atkinson et al., 1989,S 9 conclusive evidence as to the existence of all of them. 1992 ). Some of the values are different from the current The major interest in the numerous bromine oxides is due IUPAC recommendations. reflecting recent studies that have to the important role these compounds play in stratospheric not yet been accepted and incorporated into that publication. chemistry. For this reason, the spectroscopic characterization IUPAC cites the origin of their values. All citations given by of these species is mandatory in order to explain possible IUPAC are included in this article. reactions thermodynamically and kinetically and to monitor Lewis 10 in 1932 reVIewed the kinetics of reactions that the species in real time. In addition, numerous researchers proceeded with velocities ranging from the flammable region are examining bonding trends within all halogen oxide spe­ to detonation. As part of this review the author summarized cies. There are no commercial uses of the bromine oxides the kinetics of the explosion of ozone as sensitized by bro­ mentioned in the literature. mine. Lewis raised the question as to the possible formation The current study is aimed at providing a complete and of bromine oxides. thorough coverage of the literature for spectroscopic and In a 1963 review article, Schmeisser and Brandle II sum­ thermodynamic information. Although it is not the purpose marized the data pertaining to the properties and chemistry of this article to summarize and critique the chemistry of the of the halogen-oxide compounds. Although these authors did bromine oxides, all such references are provided here. The not discuss BrO, they examined BrOBr and OBrO in detail. references were obtained primarily by use of commercial ab­ A measured enthalpy of formation of OBrO(cr) was noted. stracting services and all NIST Data Centers. (Chemical Ki­ Brief mention was made of BrO 3, Br205, and Br308' al­ netics Data Center; Chemical Thermodynamics Data Center; though it was clear that the authors were not convinced that Ion Kinetics and Energetics Data Center; Molecular Spectra these "compounds" existed. Data Center; Vibrational and Electronic Energy Levels of A 1972 review by Brisdon,12 discussed seven bromine ox­ Small Polyatomic Transient Molecules; Crystal and Electron ide species: BrO, OBrO, BrOO, Br03, BrOBr, Br202. and Diffraction Data Center.) Since the literature survey revealed Br:P4' Whereas there was a complete spectroscopic charac­ so few references in total for all neutral bromine oxides, all terization of BrOBr presented, only a partial identification of citations are listed in Sec. 10 (References Annotated Bibli­ BrO was made. General comments proposing the existence ography). It should be noted that the reading of the indi­ (or nonexistence) of the remaining compounds were made. vidual articles yielded additional references. many of which Clyne and Curran 13 surveyed the reaction kinetics of halo­ are included in the attached bibliography. Not included are gen atoms, excited molecular halogens, and halogen oxide those articles or books (textbooks and handbooks) which are radicals. The authors covered the literature through early simply presenting a summary of properties. with no critical 1976. Their discussion provided a summary of the bimolecu­ evaluation. Note that the earliest reference for any bromine lar reactions ot CIU and BrU with a variety of species. In the oxide species was in 1928. Even though many of these cita­ case of BrO, one of the products formed was BrOO. Ther­ tions are not relenmt to this study. future investigators will modynamic enthalpies of reaction given in this review were not h~lxe to ,:earch the past literature. but simply concentrate extracted from earlier studies by Clyne on the publications since 199-1-. Bromine and its oxides were reviewed (through 1992) by The current version (1985) of the JANAF Thermochemi­ Keller-Rudek et af. 14 for the Gmelin series. An earlier review cal Tables" does not include any bromine oxygen species. by Kotowski et af. I:' for this series was published in 1931. whereas the 1989 version of the Thermophysical Properties The Keller-Rudek review discussed in detail many oxides of fndi\idual Substances..j. only includes BrO(g). for which 14 [BrO, Br02, Br03' Br20, BrBrO, Br202, Br203' Br20..j.. references are given: the latest of these being dated 1975. Br20:" and Br206J, but only briefly mentioned others This latter critical review referred to data from four spectro­ [BrO..j., Br06' Br207' Br30S' Br..j.O. Br..j.02, and Br..j.O..j.]. scopic studies. two micrO\vave studies. three EPR studies. Four species were listed in this review for which we do not four dissociation energy studies. and two earlier reviews. have bibliographies. Two of these species [Br..j.O, BrO(J were There are sufficient new data available to warrant a revision stated to be weak complexes, whereas the other two to this tabulation. The NBS Thermodynamic Tables:' and its [Br..j.02' Br..j.0-lJ were assumed to be unstable intermediates.

J. Phys. Chern. Ref. Data, Vol. 25, No.4, 1996 NIST -JANAF THERMOCHEMICAL TABLES FOR THE BROMINE OXIDES 1071

On the other hand, this JPCRD article mentions two species quantum-mechanical treatments) and estimations. All tables [BrOO, 02BrOBrO] which were not discussed by Keller­ are calculated using the full significance of all numeric val­ Rudek et al. l~ ues. Rounding occurs at theozone depletion," J. Pure. App!. Chern. No conclusive confirmation as to existence: Br206; 63(10), 1449-54 (1991). Br207: Br308; Br40; Br402; Br404 2M. W. Chase, "NIST-JANAF Thermochemical Tables for the oxygen fluorides," J. Phys. Chern. Ref. Data 25(2), 551-603 (1996). In the following discussions, analyses and calculations, the 3M. W. Chase, Jr, C. A. Davies, 1. R. Downey, 11'., D. A. Frurip, R. A. 1993 atomic weights of the elements 16 are used: ArCBr) McDonald, and A. N. Syverud, "1ANAF Thermochemical Tables. 3rd =79.904±0.001; Ar(O)= 15.9994±0.0003. Since the mid- Edition," 1. Phys. Chern. Ref. Data 14, Supplement No. 1. 1856 pp. 1950s, the relative atomic weight of oxygen has changed by (1985). .jL. V. Gurvich. I. V. Veyts, and C. B. Alcock, Thermodynamic Properties 0.0006 to 15.9994. Similarly for bromine, the relative atomic of Illdividual Substances, 4th ed., two parts (551 pp. and 340 pp.) (Hemi­ weight has changed by 0.012 to 79.904. Relatively speaking, sphere, New York, 1989). these ch3nres 3rt" sufficiently small that we \-vill not consider 5D. D. Wagman. W. H. Evans, V. B. Parker, R. H. Schumm, 1. Halow. S. M. Bailey, K. L. Chumey, and R. L. NuttalL "The NBS Tables of Chemi­ any conversions due to relative atomic weights. cal Thermodynamic Properties. Selected Values for Inorganic and C I and In addition, the 1986 fundamental constants are used. 17 C 2 organic substances in SI units," 1. Phys. Chem. Ref. Data 11. Supple­ The key constant of interest in this work is the ideal gas ment No.2. 393 pp. (1982). y constant: R=~.3145lU± 0.000070 J mol I K I. In compan­ 6 . P. Olushko and Y. A. Medvedev, Thermal COllSWIITS Of SubSTances. (145 pp.) (Academy of Sciences, Moscow, 1965). VoL 1. son to the 1973 fundamental constants,18 R has cham!ed bv 7W. B. De More, S. P. Sander, D:M. Golden, R. F. Hampson. M. J. 1 1 +0.0001 J mol- K- • The effect on the thennal fu~ction-s Kurylo. C. J. Howard, A. R. Ravishankara. C. E. Kolb, and M. 1. Molina. with this change is ~SO (298.15 K)=O.004 J mol- 1 K- 1 for . 'Chemical kinetics and photochemical data for use in stratospheric mod­ OBrO(g) and BrOBr(g). eling," NASA-1PL Publication 92-20 (1992); this is one of a series of similar publications. SI units are used for the final recommendations. Since we ~R. Atkinson. D. L. Baulch. R. A. Cox, R. F. Hampson. Jr., J. A. Kerr, and are dealing only \\/ith ideal gases and spectroscopic informa­ J. Troe. "Evaluated kinetic and photochemical for atmospheric chemistry: tion. the resulting calculated thermodynamic tables refer to supplement IlL" J. Phys. Chem. Ref. Data 18(2). 881-1095 (1989). thermodynamic temperatures. Thus, no temperature scale tlR. Atkinson. D. L. Baulch. R. A. Cox, R. F. Hampson. Jr .. J. A. Kerr, and 1. Troe. "Evaluated kinetic and photochemical for atmospheric chemistry: conversions are necessary. supplement IV:' 1. Phys. Chern. Ref. Data 2](6). 1125-1568 (1992). In the follO\ving dit;cut,sions, the numeric values (and their lOB. Lcwis. "Explo:>ion in gascs and thcir kinctics," Chcll1. Rcv. 10.40- 80 uncertainties jf given) presented are those reported in the (1932): particularly pp. 72-5. II M. Schmeisser and K. Brandle, "Oxides and oxyftuorides of the halo­ original publication in addition to the Sl value. This is to gens." Ad\". Inorg. Radiochem. 5. 41-89 (1963). ensure quick confirmation of the extracted results and their I:B. 1. Brisdon. "Oxides and oxvacids of (he halogens:' Int. Rev. Sci.: uncertainties. These uncertainties (not ahvays based on ex­ [norg. Chem .. Ser. One 3. 2i5-51

J. Phys. Chern. Ref. Data, Vol. 25, No.4, 1996 1072 MALCOLM W. CHASE

ume Gmelins Handbuch der Anorganisclzen Chemie (Verlag Chemie TABLE 2.1. Bromine oxide species. G.M.B.H., Berlin, 1931), 342 pp. 16IUPAC Commission on Atomic Weights and Isotopic Abundances, Chemical Abstracts and Registry

"Atomic weights of the elements 1993," J. Phys. Chern. Ref. Data 24(4), a 1561 (1995); Pure & App!. Chern. 66(12), 2423 (1994). Formula Name Deleted # Current #b 17E. R. Cohen and B. N. Taylor, "The 1986 CODATA recommended val­ BrO Bromine oxide 23878-08-2 ues of the fundamental physical constants," 1. Phys. Chern. Ref. Data BrO(BrO) Bromine oxide 77968-12-5 17(4), 1795 (1988). 15656-19-6 18E. R. Cohen and B. N. Taylor, "The 1973 least-squares adjustment of the 16651-29-9 12233-84-0 fundamental constant!;," J. Phys. Chem. Ref. Data 2,663 (1973). 9 19N. E. Holden and R.L. Martin, "Atomic Weights of Elements - 1981," 79BrO e BrO) Bromine oxide 24050-34-8 Pure App!. Chern. 55, 1101 (1983). 81BrO(81BrO) Bromine oxide 23878-08-2 2oD. B. B. Ne'umann, "NIST -JANF Thermochemical Tables, Supplement BrO:! (OBrO) Bromine oxide 21255-83-4 79 1995," J. Chern. Phys. Ref. Data, (submitted). 79BrO:! (0 BrO) Bromine oxide 29044-85-7 21 R. P. Wayne, H. Poulet, P. Briggs, J. P. Burrows, R. A. Cox, P. J. Crutzen, 81BrO:! (081 BrO) Bromine oxide 29051-09-0 G. D. Hayman, M. E. Jenkin, G. Le bras, G. K. Moortgat, U. Platt, and R. Br02 (BrOO) bromodioxy 67177-47-3 N. Schindler, "Halogen oxides: radicals, sources, and reservoirs in the Br03 (pyr) Bromine oxide 26670-64-4 32062-14-9 laboratory and in the atmosphere," Atmos. Env. 29(20), 2675-2884 BrO.j (Br04) Bromine oxide 56310-08-8 11092-92-5 (1995). Br20 (BrOBr) Bromine oxide 21308-80-5 Br2180 (BrI8OBr) Bromine oxide 21364-13-6 2. Chemical SpeCies Coverage Br20(BrBrO) Bromine oxide 68322-97-4 79Br20 (Br79BrO) 151921-01-6 81 The following is a list of all bromine oxide species cited in 81Br20 (Br BrO) 151921-02-7 the Chemical Abstract Services (CAS) Indices (formula and Br202 (BrOOBr) Bromine peroxide 96028-01-2 Br103 (OBrOBrO) Bromine oxide 55589-63-4 53809-75-9 substance). Aqueous ions and gaseous ions are not included Br203 (BrBrOJ) Bromine bromate 152172-79-7 in this study. The chemical name, formula, and CAS Regis­ Bri0.j (Br(BrO.j) Bromine 141438-65-5 try Number (when available) are given. This list is complete perbromate through Volume 121 of Chemical Abstracts Services (De­ Br20.j (02Br- Br02) Bromine oxide 53723-86-7 cember 1994). It is important to note that this listing gives Br20.j (02Br-0-BrO) Bromine oxide 55589-64-5 Br205 Bromine oxide 58572-43-3 species whose existence is now questioned. Deleted CA Reg­ Br20 6 Bromine oxide istry Numbers are given to assure the reader that all past Brl07 Bromine oxide citations were retrieved. There is limited information on the Br308 Bromine oxide 121992-88-0 existence of asymmetric isomers of the triatomic speeies­ aA secondary formula is intended to suggest the assigned structure. If there BrOO and BrBrO. Such asymmetric isomers exist for the is no secondary formula given, this means that no structure has been deter­ chlorine oxides, although for the oxygen fluorides, FOO has mined for this species, but the atomic ratio is known. been observed (but not FFO). (See Table 2.1.) blf no CA Registry Number appears in this column, the species is assumed not to exist. 3. Historical Perspective of the Bromine Oxides cher in 1928) dealt with a study in which, upon mixing bro­ mine and ozone in a flask (no temperature specified), a white . It is informative to briefly summarize the types of studies deposit appeared.,Soon thereafter, an explosion destroyed the which have been conducted through the years on the bromine apparatus. With such an auspicious debut, further studies of oxides. Specific references are given in Sec. 9. This section the bromine reaction with ozone were performed more care­ is intended to simply highlight developments through the fully and at lower temperatures (15 °C). years. not to provide specific references. For the time period 1947 to 1961 (the 5th and 6th Collec­ Using the Chemical Abstracts Services Collective Indices tive Indices), 16 additional articles were indexed in Chemical as a backdrop for these historical comments, the period of Abstracts Services. Again, this work concentrated on the 1907 to 1926 (the 1st and 2nd Collective Indices) revealed preparation of condensed phase bromine oxides and was no citations for any bromine oxide species. Even the later more definitive as to the exact composition of the compound citations do not refer to any studies in this time period or formed during a specified reaction scheme. In addition, the earlier. absorption spectra and dissociation energy of BrO(g) were In the time period 1927 to 1946 (the 3rd and 4th Collec­ reported, and the enthalpy of formation of Br02(cr) was tive Indices). Chemical Abstracts listed a total of ten cita­ measured. tions dealing with bromine oxides. All citations can be For the time period 1962 to 1971 (the 7th and 8th Collec­ grouped in two classes: (1) preparation of solid bromine ox­ tive Indices). 37 references were cited. The dominant theme ides (from the reaction of bromine and ozone) and (2) prepa­ was the formation of a particular bromine oxide species ration of 8r20 in CCI-1- solutions (from the reaction of bro­ through radiolysis. photolysis, or shock waves of solutions of mine \vith HgO). It is not always clear whether the studies' bromates (BrO, Br02' Br03) and EPR studies of prime motive was the preparation of bromine oxides or the y-irradiated crystalline bromates (BrO, Br02, Br03, and decomposition of 0 3, In all cases. the stability of the prod­ Br0-1-)' There was some additional information on the spec­ ucts was examined. The first citation (by Lewis and Schuma- troscopic properties of BrO(g), Br03' and Br20.

J. Phys. Chern. Ref. Data, Vol. 25, No.4, 1996 NIST -JANAF THERMOCHEMICAL TABLES FOR THE BROMINE OXIDES 1073

In the time period of the 9th and 10th Collective Indices For diatomic molecules, spectroscopic information on the (1972-1981), there was considerable activity in the area of electronic energy levels and vibrational-rotational structure the study of the reaction and formation of various bromine is necessary. Experimental data of these types are available oxides. In addition to the spectral studies on BrO(g), Br02' for BrO(g). Similar information on CIO(g) is available for Br03, and Br20, many were published on the preparation, comparison. structure, and Raman spectra of many of the oxides (Br203' Br204, Br20s) in the condensed phases: EPR stud­ 4.2 Thermodynamic Information ies on BrO, Br02, BrOj, and Br04 were continued. For the lith and 12th Collective Indices (1982-1991), The literature survey revealed little or no information on there were extensive studies of the formation and reaction of the thermodynamic properties of any of the bromine oxides, BrO (includiI1gmany dealing with the kinetics) in the tropo­ except for BrO(g) which was derived from spectroscopic sphere and stratosphere. Fortunately, there are numerous de­ data. There is a reference for the enthalpy of formation for finitive studies of the spectroscopic properties of the tri­ Br02(cr). Although not explicitly cited in Chemical Ab­ atomic oxides. stracts, there is a reference for the enthalpy of fonnation of In the past three years there has been experimental studies Br03(g). There are, however, numerous citations as to the in which Br02 and Br20 have been observed in the gas thermal stability of the various condensed phase oxides. phase. Additionally, more definitive studies have examined For the gas phase species, BrO(g) has dissociation energy the crystalline oxides in an attempt to confirm the existence infonnation available so that an enthalpy of fonnation may of some of the higher valence bromine oxides. be calculated. Only experimental formation information has In summary, there are no heat capacity, enthalpy, or vapor been reported in the literature for Br20(g), but not for any of pressure studies for any of the bromine oxides. There are a the other gaseous bromine oxides. few articles which detail the preparation and report decom­ There are insufficient data available to permit the calcula position temperatures for the condensed phases. There is one tion of thennodynamic functions for the condensed phase of direct experimental enthalpy of formation measurement for any of the bromine oxides. No heat capacity or enthalpy data Br02(cr), one enthalpy of formation measurement for are reported in the literature for any of these oxides. There Br20(g), and one equilibrium study for Br20(g). The spec­ are some ambiguous data for the melting of the various con­ troscopic properties and dissociation energy for BrO(g) have densed phase. been studied adequately, but the complete spectroscopic de­ tennination and enthalpy of fonnation values for any of the 5. Discussion of the Literature Data other bromine oxides is lacking. Except for Br20, not all vibrational frequencies have been observed for these oxides. The information is discussed in terms of the individual The identification and characterization of the crystalline bromine oxide species. This is not to imply that all those phase is not always definitive. species exist or have been isolated and characterized. For example, current information suggests that Br206, Br207, and Br30g do not exist, whereas compounds such as Br03 4. Summary of the Data and Br04 have been proposed but have not been isolated. for the Bromine Oxide Species The proposed existence of the former three was based on a 4.1 Spectroscopic Information chemical analysis which is now known to be in error. The references for each of the following subsections are found in The construction of thennodynamic tables for polyatomic the References-Annotated Bibliographies (Sec. 9). The gas phase species requires a knowledge of the spectroscopic squib notation is used to denote the references. The squib is constants of the molecule including electronic energy levels fonned by taking the last two digits of the year and the first and degeneracies, vibrational frequencies and molecular three letters of the lead two authors. structure (including bond angles and bond lengths). This in­ Early studies, prior to 1960. which deal with the bromine formation is necessary for any low-lying excited electronic oxides fall into three categories: (1) the reaction of bromine states. as well as the ground state. These data are obtained vvith ozone at low temperatures « -40 DC), (2) the bromine either from direct spectroscopic measurements, from theory, sensitized decomposition of ozone, and (3) the reaction of or by analogy with other similar chemical compounds. In bromine with HgO. In the former case, depending on the some cases, theoretical quantum mechanical calculations are temperature and relative concentration of the two gases, the used. There is some spectral information available on a lim­ products have been stated to be Br308, Br03' Br~05. ited number of bromine oxides in the condensed phase. Re­ Br20, and Br02. all in the condensed phase. However. due cent gas spectroscopic studies reveal structural and vibra­ to the instability of these oxides and the lack of definitive tional frequency information for BrOBr and OBrO. characterization of the crystals, it was not possible to clearly However. relying on information from the fluorine and chlo­ define the reaction and its products. Reproducibility ap­ rine oxides. estimates can be made for the structure allJ spec­ peared not to be commonplace. It was also stated that Br02 troscopic properties of the asymmetric triatomic oxides. decomposed to Br20 as the temperature was raised above BrOO(g). and BrBrO(g). -40 DC, with Br::;07 proposed as an intermediate. Since the

J. Phys. Chem. Ref. Data, Vol. 25, No.4, 1996 1074 MALCOLM W. CHASE actual chemistry is not of prime importance in this article, [89BOWIBOY], [93MON/STI] and the fact that the characterization of the compounds is not 2. EPR- definitive, these articles will not be discussed or critiqued in [66CARlLEV], [67CAR], [67CARlLEV], [67CARI detail in the sections dealing with these six species. LEV2], [67CAR/LEV3], [67CARlLEV4], [69CAR], The early studies revealed the presence of condensed [70CARlDYE], [71MIL], [71BYF/CAR], [72ADL]. phase products which were stable only at low temperatures, [72BRO/BYF], [7SDALILIN], [86BYB], [86BYB2] typically below IS 0c. Three articles by Lewis and co­ 3. Dissociation energy/IPIEA - workers examined the reaction of ozone and bromine to form [4 7COL/GAY], [48GA Y], [SOB RE/B RO], [50HER], an unstable oxide which they interpreted to be (Br30 8) n . [53BRE], [S3GA Y], [54COT], [S8BRE], [58DURI Schwarz and co-workers examined reaction schemes which RAM], [63SCH], [6SGLUIMED], [66VED/GUR], produced Br02' Br20, and Br207' Zentl and Rienacher and [68GA Y], [68WAGIEVA], [69BREIROS], [70DAR], Brenschede and Schumacher prepared Br20 by the reaction [77GLI], [77VOGIDRE], [78DUNIDYK], [79HUBI of bromine vapor on specially prepared HgO and HgO in HER], [81BOH/SEN], [82WAGIEVA], [84SAU/TAT],

CC14 solution, respectively. As already stated, these reaction [86GIN], [97BAS/GA V], [S8IGE/STO], [88SIN]. ,,('h~m~" pr()nll('~n pronllctc;: which were unstable above ap­ [88TYK], [89GURlVEY]: [92GILIPOL], [94RUSI proximately IS °C. In fact, the species of presumed compo­ BER] sition Br308 was found to be very unstable, explosively un-. 4. Formationldecompositionlreaction/detection - stable. [This compound was later shown to be most likely [40MUN/SPI], [60BRIIMAT], [60MATIDOR], Br03 . J These early preparative reports gave no quantitative [61UUb/UUU], [62UUb/PAN], [6JBUJ{JNUK], information, other than a temperature at which a (presumed) [64TRE/YAH], [66BUXlDAI], [68BUXIDAI], compound appeared to decompose. The reason for emphasiz­ [70AMIITRE], [70TOM/STU], [71KAU/KOL]. ing these points is that, even to the present, most reaction [710SL], [73DIXIPAR], [73PARlHER], [74CAH/RILl schemes for any of the bromine oxides still rely on the reac­ [77GIL/GAR], [77TAD/SHI], [78TEVIW AL]. [80SEHI tion of bromine gas and ozone in the gas phase or solution. SUD], [80YUNIPIN], [86BRU/AND], [86KREIFAB], Isolation and characterization is difficult and has led to am­ [86RAZ/DOD], [86HILIMCC], [89BARlBEC], biguous results. [90S0L], [91ARS/ZIV], [9IJAD/LON], [91NEUI DOR], [91SZAIWOJ], [92FAN/JAC], [92MCC/HEN], [92WAT], [94ARP/JOH], [94COXlCOX], [94GARI 5.1 BrO SOL], [94HAUIPLA], [94INO], [94MARlCOR], [94POMIPIQ], [95FLE/CHA] The references for BrO can be grouped into numerous 5. Kinetics - categories. Although these categories are somewhat arbi­ [70BRO/BUR], [70CLY/CRU]. [70CLY/CRU2], trary, the intent is to provide the reader with a general un­ [71 CLY ICR U], [7 5CLY IW AT], [75RADIWHI], derstanding of the information available. For the purpose of [75WOFIMCE], [76CL YIMON]. [76MOIlYUR], this article, we will discuss only the spectroscopy, EPR, and [77CLY/CUR], [77CLYIWAT], [79LEU], [79WATI dissociation energy studies; others may not be addressed as SAN], [80JAFIMAI], [80MOLIMOL], [80NIC]. these do not necessarily provide sound thermodynamic infor­ [80SAN], [8JCLYIMAC], [8 1DON/ZEL] , [8IMENI mation. SAT]. [81RAYIWAT], [81SAN/RAY], [81SANIWAT], [82ANT], [82COX/SHE], [82COX/SHE2], [82FERI 1. Spectroscopy: SMI], [83BUTIMOR], [82BAU/COX]. [84CLA], Cross sections [85BYKlGOR], [86BRU/STI], [86MCE/SAL], [88W AH/RA V], [77VOG/DRE] [86MOX], [86SAN], [86TUN/KO], [87ELO/RYN], Microwave [~"/HIUCIC], [~~BAJ{JSUL], [88tlKUrrOO], [88HIL]. [69POW/JOH], [72AMA/YOS], [74LOV/TIE]. [88HILlCIC], [88SALIWOF]. [88SAN/FRI], [88TOOI [SOLOEIMIL], [81 COH/PIC] AND], [88TOO/BRU], [89AND/BRU], [89ATK/BAU]. IR - [89ATKlBAU21 [89AUS/JONl [89FRIISA N] [R9KOI [7STEVIWAL], [SIMCK], [S4BUT/KAW]. [9 IORLI ROD], [89MEL/POU], [89SAN/FRI], [89S0LlSAN], BUR] [90DAN/CAR], [90PHI], [90POUILAN], [90POUI UV (emission) - LAN2], [90TUR]. [90TURlBIR]. [91AND/TOO]. [37VAI]. [3SVAI], [47COLIGAY] [91BARlBAS], [91LANILAV]. [91MUR], [91TUR], UV (absorption) - [91 TURlBIR]. [92POU/PIR], [92ROS/TIM]. [92W AHI [SOHER]. [SSDURlRAM], [SSZEE]. [SOLOE/MIL]. SCH], [93BRIIVEY]. [93CURlRAD]. [93MAUIW AH]. [SI BARlCOH]. [SSDUIIHUD] [93SALIWOF], [93THO/DA Y], [93WININIC], Other - [94CHIICAR]. [94THO], [94TOU], [94WEN/COH]. [72YAN]. [73BYB/SPA], [73PAN/MlT]. [74DHAI [95THOICRO] CLE]. [74DHAlCLE2]. [74TIS]. [81 DORIMEH]. 6. Review - [81GROILAU]. [85POY/PIC]. [88IGE/STO]. [48GA Y]. [50BRE/BRO], [53BRE], [53GA YJ,

J. Phys. Chern. Ref. Data, Vol. 25, No.4, 1996 NIST -JANAF THERMOCHEMICAL TABLES FOR THE BROMINE OXIDES 1075

TABLE 5.1.1. Rotational constants for BrO (Bo/cm -I).

Source 79BrO 81BrO Comments

58DURIRAM 0.455 0.472 B determined by plotting VR(J) vs (J -2)2

69POW/JOH 0.4277893 0.4260164 Beff ; microwave spectrum ±0.0000037 ±0.0000030

72AMAlYOS 0.4277789 0.4260037 Beff ; reported in MHz; ±0.0000017 ±0.0000030 microwave spectrum

74TIS 0.4282 0.4264 Review ±0.0005 ±0.0005

81COH/PIC 0.42960660 0.42782007 Beff(Be2); rotational spectrum ± 0.00000013 ±0.00000013

8IMCK 0.42960660 0.42782007 Beff ; values taken from ± 0.000000 13 ± 0.00000013 81COHIPIC; held fixed in this spectral analysis; 0.426278 0.424510 Bo values

84BUT/KAU 0.42778722 0.42601182 Beff(BO); states this values ± 0.00000007 ± 0.00000007 (from infrared and microwave data) to be same as that derived by 81 COHIPIC

910RLlBUR 0.42778706 0.42601176 derived from infrared ± 0.00000025 ± 0.000000 11 measurements

[S7RAM], [66VED/GUR], [68GA Y], [69BREIROS], emission, with a slight adjustment in the numbering scheme. [70DAR], [74LOEITIE], [74SCH], [77CLY/CUR], The vibrational analysis yielded we=771.9 cm-I and wexe [79HUB/HER], [84BAU/COX], [84BURlLAW], =6.82 em-I. [84SAU/TAT], [89ATKlBAU] Powell and Johnson [69POW/JOH] detected the micro­

Spectroscopic b~fomzation wave spectra of the gas phase BrO radical in the 2TI312 9 The microwave data which result in rotational constants ground state. They reported rotational constants BeffCBrO) are summarized in Table S.1.I. 12824.80:!:0.11 (0.42779 cm -1) and Beff(8IBrO) I Vaidya [37VAI, 38VAIJ assigned a system of bands in the 12771.6S±0.09 (0.42602 cm- ). These results are in good region 4000-4600 A to the radical Bra. The compound was agreemeIll wiLlI Lhe EPR rneasuremenlS which are memioned obtained in a flame of ethyl bromide burning with oxygen. later in this section. Vaidya proposed a provisional vibrational analysis. Coleman Using microwave detection techniques, Amano et al. and Gaydon [47COLIGAY] studied the emission of BrO in [72AM A/YOS] oe:termine:o the e:qnilihrinm strncturf', and di­ flames. A vibrational analysis yielded w~ = 713 em - I and pole moment of the gas phase BrO. They reported Beff 9 w~x~ = 7 cm - I. Zeelenberg [S8ZEE], using flash photolysis CBrO, 2TI3/2' 12824.49:!:0.OS MHz (0.42779 8I techniques with four brominated compounds, observed an em-I) and Beft< BrO, v=0)=12771.27±0.09 MHz absorptIon spectra WhICh was attributed to tirU. No vIbra­ (0.42600 cm -I). The authors recommended r e = 1. 7171 tional analysis was provided. :!:0.00I3 A for both isotopic species as derived from Be. Durie and Ramsay [S7RAM. 58DURJRAM] observed the Yanishevskii [72Y AN] studied the relationship between ;)bsorptinn spectn) of 8rO during: the flash photolysis of vibrational frequencies and dissociation energies. No new Br2-02 mixtures. Twenty absorption bands were recorded in data were presented. the region 2890-2550 A. Rotational and vibrational analy­ Byberg and Spanget-Larsen [73BYB/SPA] used a modi­ ses \-vere performed. leading to values for 1'0, and Bo, as well fied extended Huckel method to calculate nuclear quadrupole as We and wexe values. Only approKimate rotational constants coupling constants. No new structural information for BrO \vere observed: was provided. 'l)BrO Bn = 0.455 cm - I ro = 1.669 A Pandey et al. [73PAN/MIT] calculated the mean ampli­ tudes ot Vlbration ot tirU at the temperatures T=LYl:).lb and SIBrO B()=0.472 em-I l'o=1.635 A 500 K. The bond and molecular polarizabilities have been I?urie and Ramsay adopted a mean value of 1'0 = 1.65 :!:0.02 computed using the Lipincott-Stutman Ll-potential function A. The authors were able to describe the absorption bands in model of chemical bonding. the same \'ibrational scheme as used by 47COL/GA Y for Dhar and Cleveland [74DHA/CLE, 74DHA/CLE2] pre-

J. Phys. Chern. Ref. Data, Vol. 25, No.4, 1996 1076 MALCOLM W. CHASE sen ted calculations relating the Morse-potential energy func­ lar parameters of BrO in the 2rr 3/2 state were observed by tion with force constants, vibrational frequencies and disso­ Cohen et al. [81COHIPICl Rotational constants for the I ciation energies. Calculations refer back to the Durie and 2rr3/2 state were determined to be Be2 =0.42960133 cm- Ramsay (1958) study. No new data were provided. C9BrO) and 0.42781482 cm-1 ( 81 BrO). The values of We2 1 9 1 In their review of microwave spectra of diatomic mol­ =726 cm- C BrO), 724 cm- (81BrO) and We2Xe2=4.92 ecules, Lovas and Tiemann [74LOVITIE] recommended ro­ cm- I C9BrO), 4.90 cm -I (81BrO) derived from the me­ tational constants and ground state splitting based on data chanical constants were in good agreement with results ob­ from Amano et al. (1972). However, they also referred to the tained by [81BARlCOH], [7STEVIWAL] and [80LOEI EPR results of [67CARlLEV3] and [71BYF/CAR]. MILl An re2 value of 1.717263 A was also determined for Tischer [74TIS] analyzed the x2rr3/2 spectrum of the BrO both of the isotopic species. radical by calculating energy eigenvalues of the correspond­ Doraiswamy and Mehrotra [81DORIMEH] examined the ing Hamiltonian. The author adopted [70CARlDYE]'s EPR collision-induced linewidths of BrO. value of B =0.4282 cm- 1 9BrO); B =0.4264 cm-I o C o Grodzicke et al. [81GROILAU] calculated the dipole mo­ (81 B rO) for the rotational constants and Ao = - 815 ± 120 ment of BrO. cm -I for the splitting of the two isotopic species (see the Using laser magnetiC resonance spectroscopy on three next section). An ro = 1.7205 A C9BrO) value was also CO2 laser lines, McKellar [81MCK] detected magnetic di­ quoted from [70CARlDYE]. re values of 1.717 A were like­ pole transitions between the 2Il1/2 and 2Il3/2 components of wise reported, based on the work of Amano et al. (I972) for the grollnn staff' of RrO This W::lS thf' first direct observ3tion both isotopic species. of the 2Il1/2 state of Bra. A spectrum lying between 964.77 Tevault et al. [78TEVIW AL] studied the reaction of and 969.14 cm -1 was recorded for this state. The spin-orbit atomic and molecular bromine with atomic and molecular eff splitting parameter A and rotational constants B eIl ) oxygen in argon matrices (photolysis of bromine and ozone ll2 were determined to be -967.9831 cm- I (I'JBrO), containing matrices). Several bromine oxygen compounds -967.9981 cm-I (81BrO) and 0.4248 cm-1 C9BrO), 0.4230 were stated to have been formed and identified by infrared 1 8I cm- ( BrO), respectively. The author also predicted micro­ spectroscopy-BrO, OBrO, BrBrO, BrOBr, and (BrOh. The 2 wave rotational transition frequencies for the x rr 1I2 state of authors assigned a very weak absorption at 729.9 cm -I to BrO. BrO. The force constant calculated from this frequency was Butler et al. [84BUT/KA W] observed the fundamental 4.18 mdynJA, a value which was not unexpected on the basis vibration-rotation band of the 79BrO and 81BrO radicals in of the FO and CIO constants of 5.41 and 4.66 mdynJA re­ the 2rr3/2 ground electronic state (700-760 cm - 1) by using spectively, obtained from their argon matrix frequencies. A reinterpretation of the data yielded We = 751 em -I and wexe Zeeman-modulated IR diode laser spectrometry. The authors assigned a 721. 92814 cm - I value for the 81 BrO A 2rr i­ = 5.0 cm -I for the ground state. The excited state was re­ 2 x rrj transition, which agrees well with the 714 cm - I value ported to lie at 27740 cm -I. I Absorption spectra of BrO were observed from argon ma­ estimated by [81COHIPIC] and the 722.1±1.1 cm- value trix samples prepared by microwave discharge of mixtures of derived by [81BARICOH] from optical spectra. Rotational 1 9 argon, bromine and oxygen by Loewenschuss et [80LOEI constants 8 0 =0.427781964 cm- C BrO),=0.426006591 at. 1 8I I MILl The authors reported an excited state of Te=26363 cm- ( BrO), Q.armonic .frequency we=732.S9 cm- 9 1 8I cm- I with we=514.8 cm- I and wexe=4.8 cm-I. Vibrational e BrO),=731.37 -cm- ( BrO), and vibrational anharmo­ 1 9 I 81 const::lnts for the erollnn st::ltf' ::lrf' frle=741.') cm- I ::lnn (,leXe nicity W eXe=4.74 cm- e BrO),=4.72 cm- ( BrO) were =6 cm-I. These values result from a reanalysis of earlier calculated. But based on the equilibrium spin-orbit coupling data and the current matrix work of [80LOEIMIL]. constant Ae , assumed to be independent of isotopic mass, the I The absorption spectra and rotational analysis of the "true" we=72S.69 and 724.18 cm- for the two isotopic 1 9 A~lli-X :::U i state of isotopically enriched 151BrO and normal species. The Ae value of -975.19 cm- e BrO) was based BrO have been obtained by Barnett et al. [81 BARICOH] us­ on the results of [82MAKILOV] for CIa. The eqUilibrium ing the flash photolysis of mixtures of bromine and ozonized internuclear distance was calculated from rotational con­ oxygen. The authors quoted and used [81MCKJ's value of stants to be r c= 17207') A for hoth of th~ i(mtopic. species. -968 em -I as the spin splitting in the ground state. The Duignan and Hudgens [85DUI/HUD] reported the reso­ lower state rotational constants were taken to be those de­ nance enhanced multi photon ionization spectra of CIO and ri ved from the microwave study [Sl COH/PICl The rota­ BrO free radicals between 415 and 475 nm. BrO showed tional constants for the excited state were estimated as: B ~ three new vibrational progressions starting from transitions =0.31-+ cm- I and a; =0.003-+ em-I. with an internuclea-~ between the X 2rr3/2 state to Rydberg states with assignments distance of 1.95 A. From the analysis of vibrational assign­ of E22:( voo=65003 em-I), F2L( voo=67470 em-I), and an ments for BrO. a value for ~ G'{/2 of 722.1 ± 1.1 em -I was apparently inverted state, G( voo=70504 em -I). No doublet obtained. tv'lolecular constant values of w~: =730.6 em -I. originating from the ground state 2rr 1/2-2rr 312 spin-orbit w;=516.1 em-I. and D~=19694 em- I w~re used for the splitting was observed. The authors proposed a ground state calculations of the v' and v' bands. vibrational frequency of 714 em -I. obtained from the differ­ Rotational spectrum of the v=O and 1 bands and moleeu- ence of the hot band at 466.51 nm and the E(O,O) band. This

J. Phys. Chern. Ref. Data, Vol. 25, No.4, 1996 NIST-JANAF THERMOCHEMICAL TABLES FOR THE BROMINE OXIDES 1077

TABLE 5.1.2. Rotational and electronic state splitting constants for BrO.

Source Species Balcm- 1 Alcm- 1 ra /A

66CARILEV 79BrO 0.45 81BrO 0.47 70CARIDYE 79BrO 0.4282::!:: 0.0005 -8 IS::!:: 120 1.720" 81BrO 0.4264::!:: 0.0005 -815::!:: 120 71MIL BrO adopted values of [70CARIDYE] 72ADL RrO adopted values of [70CARJDYE] 72BROIBYF 79BrO 0.4281 -980 81BrO 0.4263 -980 81MCK 79BrO O.4278 b -967.983(2) 81BrO 0.4260b -967.9981 (2)

"Unspecified which BrO isomer e9BrO or 81BrO) it dealt with. "These values are Befferr 3/2).

9 value differed from the 722 cm -1 value proposed by C BrO) and 8 0 =0.42601176 (81BrO) were also obtained. [78TEV/wAL, 81BAR/COH, 84BUT/KAW], and the FZL The molecular constants are in good agreement with those I I 2 (we=822 cm- ), E2L(We=897 cm- ), and G (LlGl/z =848 reported by [84BUT/KAU]. cm - I) values for the Rydberg states. Values for EZL( wexe The photoionization spectrum of 79BrO was measured by I =2.6 cm- ) were also given. Monks et al. [93MON/STI] over the wavelength range Poynter and Plckett [~5POY/PIC] have created a A= 1U~-122 nm (~196 7 -92593 cm -I) using a dischargeflow computer-accessible catalog of submillimeter, millimeter and photoionization mass spectrometry. The structure shown by microwave spectral lines which was constructed by using the equivalent 81 BrO spectrum was indistinguishable. This is . theoretical least square fits to the observed spectral lines. the first determination of the ionization energy for Ground-state properties of the fourth row main group BrO(X2nD to be obtained via direct photoionization thresh­ monohydrides XH and monoxides XO (X = K through Br) old measurement, although it had been attempted by Dun­ were determined by Igel-Mann et al. [88IGE/STO] by means lavey et al. [78DUNIDYK] earlier. A vertical excitation en­ of self-consistent field/configuration interaction (SCF/CI) ergy for the X --* A transition was calculated (using MC-SCF calculations. Bond lengths re= l.741 A (3.29 a.u.), dissocia­ method) to be 30539 em -1 which compares favorably with 1 tion energy De= 10646 cm- (1.32 eV) and vibrational fre­ an experimental adiabatic excitation energy 27926 em -I. quency w e=726± 10 cm -1 were calculated. The authors re­ This study also provides calculated values for three other ferred to the dissociation energy recommended by Huber and excited electronic states. The authors quoted the three ex­ Herzberg (1979). cited states of [85DUIIHUD]. An re= 1.824 A value was also Wahner et al. [88WAHIRAV] measured the absolute UV proposed. cross section of BrO at 338.1±0.1 nm, the peak of the (7,0) EPR Information band of the A 2n f-X zn transition. The absorption spectra of BrO in the wavelength range 312-385 nm were measured at There are numerous EPR studies involving BrO. These 298±2 and 223±4 K using a flow tube reaction. studies can provide information as to the rotational constant Bowmaker and Boyd [89BOW/BOY] performed a (to yield an ro value) and the electronic spin orbit splitting SCF-MS-Xa study of the bonding and nuclear quadrupole constant (A), and are summarized in Table 5.1.2. In many of coupling in oxygen compounds with the halogens. Calcula­ these studies this information has not been provided. tions were performed using structural information from Carrington and co-workers have studied the EPR spectrum [69POW/JOH]. of BrO in the gas phase. In all cases there were difficulties in 2 preparing the sample and observing the full spectrum due to The v= 1-0 band of BrO in the X n 312 spin state was measured by Orlando et al. [910RLIBUR] using high­ the intensity of O2 lines in the same region. resolution Fourier transform absorption spectroscopy. The 66CARILEV - A preliminary EPR study in which techniques values obtained were vo=723.4l4 e9BrO) and vo =72l.927 for measurements were given for BrO. Eighteen lines of (8I BrO)' One hundred and thirty transitions were assigned the 24 expected were detected, the remaining being ob­ and analvzed to determine the band origins and rotational scured by the intense spectrum of O2. The authors were constant; of 79BrO and 8IBrO. The BrO line positions were confident that the spectrum arises from BrO (2n 312) in its fit using the same expression as [84BUT/KA W]. The fits lowest rotational level. The data were consistent with Du­ also included the micfO\vavc data of [81 COHIPICl This fit rie and Ramsay's (1958) calculations for the rotational 79 8I involved the band origin rotational constant and centrifugal constant 8 0 =0.45 ( BrO); =0.47 ( BrO). distortion constant. UV measurements recorded an A2n­ 67CAR - A review article of EPR and other forms of micro­ X 2n transition' of BrO in the region 285-355 nm (28169- wave spectroscopy in which the BrO spectra was men­ 35088 em-I). Rotational c~nstants. 8 0 =0.42778706 tioned but no data was given.

J. Phys. Chern. Ref. Data, Vol. 25, No.4, 1996 1078 MALCOLM W. CHASE

67CARILEV - Attempted to study the EPR gas phase spectra [75DALILIN] deals with BrO, in fact it examines the EPR of of BrO. The relatively weak BrO lines were often ob­ Br02' Br04, and Br06 and is strictly a theoretical study.

scured by the many intense O2 lines which occur in the Byberg [86BYB] studied the EPR of [XO, O2], X=Br, CI, same field region. formed from the decomposition of CI03- and Br03 - in solid 67CARlLEV2 - The effects of an electric field on the elec­ KCI04 : KBr03' The main features of the spin Hamiltonian tron resonance spectra in the gas-phase were used to mea­ [BrO, O2] correspond to BrO err) in a crystal field, coupled sure the dipole moment of BrO in its electronic ground through an isotropic exchange interaction to O2 (3I ~) to state. form a spin-doublet ground state. Hamiltonian values were 67CARILEV3 - Examined the EPR spectrum of BrO and given as experimental and calculated values at 26 K. Mo­ detected ,double quantum transitions. lecular hyperfine parameters in MHz for 79BrO in the gas 67CARlLEV4 - A gas phase EPR cavity was developed phase were also given. which allows the application of a parallel Stark field. The In a subsequent study by Byberg [86BYB2]. the prepara­ spectra of BrO were observed clearly in the presence of tion of BrO in the crystal state was examined. The EPR and O , 2 x-irradiation of solid KBr03 is shown to produce complex 69CAR - High-resolution spectroscopic studies of the rota­ defects of the composition [BrO, 02]. The EPR spectra of tional levels of BrO. The author reviewed his previous KBr03(cr) recorded at 26 K after x-irradiation contained sig­ studies involving the 312 electronic state of BrO. 2n nals from at least six defects in spin-doublet and ground 70CARfDYE - The gas phase EPR spectra of BrO in its state. But the thermal formation of [BrO, O ] in the photo­ 2IT 312, J = 3/2 levels were described. The analysis con­ 2 lyzed KBr03(cr) indicated that BrOt produced [BrO, O2] by firmed that the radical has a 2 rr 3/2 ground electronic state reaction with a photoinduced precursor R, BrOj + R (8612.200 MHz). Values of the fine-structure splitting A -+[BrO, 02]. (See Table 5.1.2.) = - 815 ± 120 cm -I and rotational constant B 0 = 0.4282 The cunclusiuns tu be drawn from Ihe EPR smdies are Ihar ±0.0005 cm- I e9BrO); =0.4264±0.0005 cm- I (8IBrO) the ground state is 2rr (inverted doublet). For comparison, were obtained. The determination of A as negative 3/2 the laser magnetic resonance study of [8IMCK] yielded ro­ showed conclusively that the ground state was 2rr3/2 (an inverted doublet). The authors favor their values over tational and spin orbit coupling constants. These values are those obtained by 58DURlRAM, leading to a calculation included in Table 5.1.2. of "0= 1.720 A. Dissociation Energy Studies Byfleet et al. [7lBYF/CAR] measured the dipole moment There are two experimental spectroscopic studies which of BrO using Stark splitting of the molecule's gas phase yield dissociation energy values: [47COL/GA Y, 58DURI electron resonance spectra. RAM]. It is important to note that the excited state dissoci­ Miller [71MIL] reanalyzed the data from electron reso­ ates to Brep3/2 ) +0(,D2). nance experiments for BrO and 10. Although he stated that 1. A linear Birge-Sponer extrapolation of the Coleman the splitting of the ground state was anomolously low for 10 and Gaydon (1947) data gave 17800 cm- l (2.21 eV or and questioned the treatment for BrO. he did not give a new 50.9 kcal) for the dissociation energy of the ground value for the splitting of the ground state for BrO. Miller state. Assuming that this extrapolation is high by per­ quoted the earlier results tabulated by [70CARfDYE] for the haps as much as 20% [53GAY], Coleman and Gaydon spin-orbit coupling constant (A = - 815 cm -I). recommended 14240 cm- I (1.75±0.3 eV or 40.7 kcal). Adl [72ADL] examined the EPR spectrum of gaseous 2. As stated by Durie and Ramsay .[58DURlRAM], the BrO. He identified as the ground state a 2rr electronic state absorption spectrum of BrO was not observed to the for the radical \vhere J=312. [72ADL] compares and con­ dissociation energy limit. The limit was determined by trasts ground and first excited rotational states of BrO, as­ extrapolating an equation representing the band heads signing the radical a spectra of 8775.5 MHz for both the and by a graphical Birge-Sponer technique. The limit Qround state (J=312) and the excited state (J=512l. The mo­ was determined to be approximately 35200 em -I. Sub­ lecular parameters presented by [70CARIDYE] were used to tracting the ID - 3P excitation energy of the oxygen calculate the "pectra for the .1=112 and .1=':>12 levels of BrO_ 2 2 arom (15867.862 cm-'), the dissociarion energy is cal­ No new parameters were presented by Ad!. culated to be 19332±200 cm- I (2.40±0.02 eV or 55.3 The EPR spectrum of the gaseous BrO J=5/2 rotational kcaIlmol). Durie and Ramsay reported the dissociation lewis of 2n ground state \vas observed by Brown et al. energy to be 19330 cm -I whereas the actual calculation [72BRO/BYF]. A comparison with the results of J=312 lev­ yields 19332 cm -I. els lead to values for corrections. Spectra were recorded at 9720.26 YIHz at J=512 levels using Stark modulation. This Table 5.1.3 lists all studies which mention the dissociation value. -980 cm -I. is preferred to that of [70CARIDYE] energy of BrO. There are numerous articles which refer to because of the more extensive data in the higher order data dissociation studies, some of which simply extract earlier treatment method used by [72BRO/BYF] in comparison with reported values or calculate them anew, and others which that used by [70CAR/DYE]. reassess data from the two experimental spectroscopic stud­ Although secondary references imply that the article by ies listed above.

J. Phys. Chem. Ref. Data. Vol. 25, No.4, 1996 NIST -JANAF THERMOCHEMICAL TABLES FOR THE BROMINE OXIDES 1079

TABLE 5.1.3. Dissociation energy of BrO (DoO).

Source eV kcallmol kllmol Comments

Experimental 47COLIGAY 40.7 170 See discussion 58DURIRAM 55.3 231 See discussion

Calculation 77GLl 50.9 213 Used experimental !1Hr values to calculate mean bond dissociation energies; the calculated DI value was derived from a t1Hr value of [S3BRE] but this latter value was not reported 881GE/STO 1.32 127 SCF/CI calculations of the fourth row main group oxides (for the oxides K through Br the De values are consistently underestimated except for KO); dissociation energy value compared with a 2.45 cV value presumably from [79HUB/HER) (This is not what appears in these authors' book); bond length re= 1.741 A and vibrational frequency w c =726= 10 cm -I were also calculated

Comparisons 77VOGIDRE Used value extracted from [68GA Y] 78DUNIDYK Photoelectron spectroscopy study of ionization potential: quotes dissociation value of [S8DURIRAM] 81 BOH/SEN Mentioned dissociation energy but did not give a value 84SAlJITAT Adopted value recommended by [79HUB/HER] 88TYK Reported values extracted from existent sources: no new data 92GILIPOL Photoelectron spectroscopic study: no new values given

Re-assignments 50BRE/BRO No direct values are given 50HER 2.2 212 Also refers to US eV as derived from f.47COLIGA YJ 53BRE No value given but reference made to an earlier study [SOBRO/BRE] 53GAY 1.8:±:0.5 42 176:±:48 Linear Birge-Spone extrapolation (L.B.x.) (v. 0-7) 2.2 e V. but signs of negative curvature: analogy with CIO and 10 favors high value; [47COLIGAY] 54COT 2.2 212 Values extracted from [50HER] and [53GA YJ respectively: 1..8:±:0.5 176:±:48 spectroscopic evidence is uncertain; Gaydon's upper limit. which agrees with [50HER] LBSX value, is more in accord \vith Dc.(CIO), but even this seems low 58BRE 5J 213 Value reported by Brewer with no explanation as to its origin 63SCH 1.8:±:0.5 176:±:48 Value extracted from [53GAY] 65GLU/MEO 55.3:±:0.6 231:±: 3 Values hased primarily on the study of [58DUR/RAM] 66VED/GUR 55.3:±: 0.6 231 :±:3 Extrapolation of A 2n levels: assumed dissociation I imi l goes to BreP3/:)+O('D); interpretation taken from Gurvich's carly review (I <)62) 68GAY 2.40:±: 0.02 55.2 231 L.B-S.Xcn 2.7. eV. Good .G.B.-S.A 2ft assuming limit is to O(,D). 2.402:0.02. [58DURIRAM] 68WAGIEVA 55.3:±: 0.6 231 :±:3 Results hased solely on the work of [58DCRIRAM] 70DAR 55.2 231 Spectroscopy. adopted !:38DUR/RAMJ value: 55.3:±:0.6 231=3 Extrapolation of Acn [66VEDlGUR]: 55.27 231 Extracted from[65W AG/EV A]; 55.3:±: 0.1 231:±: I Recommended by [70DAR] 70Hl'B/HER :2.39::::0.01 ::1:<0.6:::: I.n Tuken from nellr convergence of the i1b~Orplion b'lI1d~ A - X I .

assumes dissociation of A into Br(2Pld -or '02) :-::2\\'.-\G/I::V'\ 55.3=0.6 231:!: .3 Results based solely on the work of [580UR/RAM] ~9CiCR/VEY 55.28=0.6 23\J:±: 3 Based on short extrapolation of the levels in the A:n; state: authors tnenli()ll rhree kint'lir ~1lJ(lif''' whi"h If'ilel III I,',,, :1('('llnltt' \':1111<"<; 94Rl'SIBER 55.3=0.6 231 =3 Value given at () K: source of \'aluc unknown

Clyne and CO-\v'orkers [77CL YfW AT. 77CL Y/CUR] tabu­ 5.2. Br02 (OBrO) lated enthalpy of reaction for reactions involving BrO. The enthalpy of formation in these calculutions was not specifi­ All references dealing with RrO~ are listed in the follow­ cally gi\en but was said to have been taken from the best ing eight categories. This listing is somewhat arbitrary but is <)\'ailabk information at the time (1976). intended to give the reader a purview of the reported data. Of \Ve adopt the interpretation of [79HUB/HER] for the dis­ prime interest for this article are the spectroscopic and bond c-;uciarion energy uf BrO. (See Table: 5.1.3. ) dissociation energy ~tl\dies.

J. Phys. Chem. Ref. Data, Vol. 25, No.4, 1996 1080 MALCOLM W. CHASE

1. Formation/preparation/decomposition and Keith [74S0L/KEI] made several ~ttempts to prepare [37SCH/SCH], [3SSCHlWIE], [39SCHlJAB], Br02, including the glow-discharge method of [37SCHI [39SCHlWIE],. [40MUN/SPI], [59SCHlJOE], SCH]. The techniques used produced bromine oxides of vari­ [62GUEIPAN], [71SHErrUR], [74S0L/KEI], able composition including Br02, Br03 and Br02.71 (very [SOJAFIMAI], [S3BUTIMOR], [90LEV/OGD] close to Br308)' Much of this work was reviewed by 2. Formation in crystal matrix or solution - [63SCHlBRA] and [72BRI], as well as in the Gmelin series [62BOY/GRA], [6SBUXlDAI], [69AMIICZA], mentioned in the Introduction. [69BARlGIL], [70AMIffRE], [710SL], [91SZAI There are numerous EPR studies. None of these studies WOJ] provide any information as to the structure of Br02 . a$ an intermediate - 3. Br02 Chase and Boyd [66CHAlBOY]: radiolysis of crystalline [S5BEN/KRI], [S5STE], [S6BEN/KRI, [90SASIHUI] alkaline earth bromates by cobalt-60 y-ray, suggested that 4. Reaction - Br02 was produced and stabilized in the crystal lattice. [53PFL], [55PFL], [72FIEIKOR], [76HERlSCH], [7SFOE/SCH], [SOFOEILAM], [SOFOEILAM2], Collins et al. [70COL/COS]: irradiated zinc bromate, ex­ [S2FOEILAM], [S2FOEILAM2], [S2FIE/RAG], perimental evidence suggested the formation of a para­ [83FIEIRAG], [S3FOEILAM], [S5FOEILAM], magnetic center In the crystal which was attributed to [S6HUIINET], [SSNETIHUI], [89FOEINOS], Br02' [91SZAlWOJ], [94HJEIROS] Byberg [71BYBJ: x-ray irradiated KBr04 crystals at 10 or 5. Enthalpy of formation/bond di~~ociatioIl eIlelgy - 26 K, spectra interpreted to indicate the existence of [51PFLlSCH], [54COT], [66VED/GUR], [68WAGI Br04 which then, thermally dissociated to Br02' EVA], [S2WAGIEVA], [S9STA], [95HUIILAS] Rao and Symons [72RAO/SYM]: x-ray irradiated crystal­ 6. Spectroscopy/structure - line bromate5, EPR 5peclra of Br02 ill pilll uil~eu UIl ~ee­ [73BYB/SPA], [73PASIPOT], [76PAS/PAV], ing the effects of two isotopes 79Br and 81Br, both having [78TEVIW AL], [83BUTIMOR], [S9BOWIBOY], 1=3/2, proposed a formation route for Br02, results [94RAT/JON], [95MAIIBOT], [95MUEIMIL] stated to differ from the Collins et al. [70COL/COS] data. 7. EPR- [66CHAlBOY], [70COL/COS], [71BYB], [72RAOI Byberg and Linderberg [75BYBILIN]: x-ray irradiated SYM], [75BYBILIN], [75DALILIN], [77SASIRAO], perbromate crystals, suggested the formation of a weakly [79CARISAH] bound complex of the composition (Br02- O2), no evi­ 8. Review - dence that Br02 existed as a separate entity. [60GEO], [63SCHIBRA], [72BRI], [S4BURlLAW], Dalgard and Linderberg [75DALILIN]: molecular theory [S4JAC], [90JAC], [94JAC] calculational model for the EPR study of quadrupole and Br02 was first mentioned in the literature in 1937 [37SCHI hyperfine interaction tensors of Br02, Br04, and Br06; SCH]. Schwarz et al. [37SCHlSCH], [3SSCHIWIE], x-ray irradiation of KBr04 led to the formation of the [39SCH/JAB], [39SCHIWIE] discussed the preparation of (Br02 . O2) complex. Br02' Sastry and Rao [77SASIRAO]: EPR identification of the Schwarz and Schmeisser [37SCH/SCH] studied the reac­ formation of Br02 in a y-irradiated cadmium bromate di­ tion of bromine with ozone which produced Br02 as a light hydrate. yellow solid. This compound did not melt but decomposed Carlier et al. [79CARIISAH]: EPR of Br02' spectrum spontaneously to the elements at approximately O°c. was similar to that observed by [72RAO/SYM]. Schwarz and Wiele [3SSCHIWIE] studied the thermal de­ composition of Br02' In addition to the formation of the There are a number of spectroscopic studies which pro­ elements. the authors also detected a white oxide which they vide vibrational frequencies and sIrucrural information. presumed was Br207 or Br206 and a dark-brown oxide. These are summarized in Table 6. 8r20. Schwarz and Wiele [39SCHIWIE] continued their Byberg et al. [73BYB/SPA], stated that in 1973, no struc­ <;;tlld y· of thf' thE'rmal dE'composition of BrO:! Their study tural information was availahle for Br02. Modified extended shO\\'ed that Br02 is completely stable at -40°C, but that Huckel theory was used to calculate nuclear quadrupole cou­ decomposition can be detected manometrically as the tem­ pling constants. Comparing calculated values with observed perature is increased. Br20 is stable at -40°C. Again values helped confirm the geometry of Br02: C 2L, symmetry 8r:::07 was suggested as one of the decomposition products with a bond length of 1.625 A and a bond angle of 117.6°. of BrO,. This geometry was that of CI02 with an adjustment for the \lungen and Spinks [40i\1UN/SPI]. in examining the de­ presumed differences in BrO and CIO. The nuclear quadru­ composition of ozone in the presence of bromine, detected pole coupling constants are not as sensitive to the bond angle the formation of a number of bromine oxides. including as they are to the bond distances. The authors stated that any Br02' reasonable changes will not improve interpretation. The remaining studies of the formation of Br02 are based Pascal et al. [73PASIPOT, 76PASIPAV] indicated that on \·ariations of these abO\·e-mentioned procedures. Solomon Br02 exists as Br20-i with a Br-Br bond. The authors ob-

J. Phys. Chern. Ref. Data, Vol. 25, No.4, 1996 NIST-JANAF THERMOCHEMICAL TABLES FOR THE BROMINE OXIDES 1081

Table 6. Polyatomic bromine oxide species: Structure and vibrational frequencies.

Bond Distance rCA) Vibrational Frequencies

Source Structure Br-O 0-0 Br-Br comments

Br02 (OBrO) 73BYB/SPA C 2v ' 117.6° 1.625 Modified extended Huckel theory used to calculate nuclear quadrupole coupling constants; calculated values for structure

73PASIPOT Raman spectra in crysralline form indicated that Br02 exists as Br20~ with a Br-Br bond

78TEVIWAL '*1l0:±:2° 852 Infrared spectra of the isolated radical in an Ar matrix; *apex angle 18 determined on identification of v3 asymmetric stretch; 0 isotopic enrichment experiments used to identify molecules

83BUTIMOR C2l" 118° 2.9 Mass spectrometry; discharge-flow system; reaction of 0+ Bf2 ; assumed structure (in analogy with OCIO) and calculated rotational consrants

84JAC, 852 Review recommended V3 value from Ar matrix study of 78TEV/ 90JAC WAL 94JAC

89BOW/BOY C tV' 117.6° 1.625 SCF multiple scattering X-a calculations of the bonding and nuclear quadrupole coupling in Br02; adopted geometry of [73BYB/SPA]

95MAVBOT Czv 081BrO o 81BrO IR absorption; matrix isolation at 12 K 791-797 842-844 079BrO 079BrO 794-799 845-847

95MUEIMIL C 2v , 114.4° 1.649 Microwave study, preliminary analysis also supportive of V2 approximately equal to 300 cm- I

BrOO 70CLY/CRU Electronic absorption spectrophotometry in a discharge-flow system of BrO; formation of BrOO in BrO+BrO-kr -+Br+BrOO-)Br+02 disproportionation reaction

78TEV/SMA 1487 Infrared spectra of the isolated radical in an argon matrix

79MICIPAY 872 100 BEBO calculations, stated to be indeterminate for the bending frequency; value suggested for Vz is consistent with the authors' kinetic data in the region 200-360 K

83BUTIMOR Cs ,120° 2 1.5 Mass spectrometry\discharge-fiow system; assumed structure (in analogy with Br-O-O-Br structure suggested by 70CLY/CRU) and calculated rotational constants

84JAC. 1487 Review recommended VI value from Ar matrix study of 78TEV/ 90JAC SMA

95MAVBOT Cs Brl602 IR absorption; matrix isolation at 12 K; the vibrational frequency 1'+75.5-1484.0 assigned to Brl60lS0 is in fact a mixture of Brl60180 and Brl60180 Br\80160 1.+30-1432.1

VI V2 V3 V~

56VEN/SUN C ol,,89° 1.68 442 800 35 828 References observed Raman frequencies, however it appears adopted 0 frequencies are approximations derived from the ion: bond distance calculated by Badger's rule; calculation of force constants

63VEN/RAJ .+42 800 35 828 Urey-Bradley potential force field; although the authors refer to .+39 806 0 815 observed vibrational frequencies there is no specific reference to 35 these observations; observed and calculated frequencies given 0 respectively: calculation of force constants

6.+RAO/SYM Vibrational mean square amplitude theory; two totally symmetric AI and identifies six vibrations, modes; no data provided: two doubly degenerate E mean square amplitudes calculated

J. Phys. Chern. Ref. Data, Vol. 25, No.4, 1996 1082 MALCOLM W. CHASE

Table 6. (Continued.)

Bond Distance rCA) Vibrational Frequencies

Source Structure Br-O 0-0 Br-Br Comments

70BEG/SUB ESR; formation of Br03 from y-radiolysis of potassium bromate at 77 K; structure identified; magnetic parameters given

72RAO Centrifugal distortion constants; classifies the six vibrations as two totally symmetric AI and two doubly degenerate E modes but no values were given

74BYB/KIR * Cs *ESR crystal study of paramagnetic defects in x-in'adiated KBr03 suggests that the species is Br03 rather than Br03; KN03: KBr03 exhibits the Br03 species with a cylindrical spin Hamiltonian

analogous to that of CI03 ; calculated bond distance based on CI03

77LEE/BEN 1.66 EXAFS spectra: prediction of bond length

78THIIMOH 1.79 800 442 82 350 Group theoretical method; vibrational frequencies calculated for VI and V2 are reversed, the same is true for V3 and v-I: force constants are calculated

85BYB 1.57 Values proposed earlier by 74BYB/KIR to account for the spin

Hamiltonian of Br03 in KN03 : KBr03 ;

105S 1.56 1.72 1.64 ESR spectra in KCI04 : KBr03; author proposes a new asymmetric structure for Br03 with bond distances for (Br-O~), (Br-02) and (Br-03), respectively

86UMAIRAM ESR y-irradiation of crystal KBr03 and Sr(Br03h·Hp; MO calculations using the CNDO/2 method; NQR experimental values

BrOBr

54ANT/DOJ UV absorplion spectra of Br20 in CC14 ; strong absorprion band ar 2800 A (35714 em-I)

68CAMIJON 504 197 581 IR spectra of the crystal Br20 and 180-enriched Br20;spectra most satisfactorily explained in terms of C 2v symmetry; comparisons with F20 and Cl20 were used in explaining data; force constants were calculated

72BRI 504 197 583 Review based crystal study by 68CAMIJON; calculation of force conSlams

77PASIPAV 504 197 590 Raman analysis' (species observed in a matrix at 50°C) corroborates previous IR studies; assumed the formation of Br20 from

decomposition of Br20J

78PAS 506 592 IR spectra of the crystal Br20

78TEVIWAL 526.1 504 IR spectra of the isolated radical in an argon matrix; states that the values assigned by 68CAM/JON for VI and V3 are reversed and 18 questioned the V3 reasonableness of the bond angle: 0 isotopic enrichment experiments used

8-1-BOLIBAL Linear 250 245 800 Extended x-ray absorption spectra of thermally excited vibrations; frequencies were used to calculate force constants; no preferred structure was recommended; estimates of the vibrational frequencies as a furction of bond angles

84CPIILAR MOVD theory: no data provided

8-1-JAC. 526.1 623,4 Re\'iew recommended j)1 and P, values from Ar matrix studies by 90JAC. 78TEV/WAL and 87ALLIPOL 9-1-JAC 87ALLIPOL *IIV or 8r 526.1 623,4 IR spectra of matrix isolated radical: *bond angle depend on relative assignment of VI and fl.,

90LEY/OGD C~l' Ill::::::''' 1.85 3.07 508 595 IR and CY -YIS spectroscopy and bromine k-edge EXAFS of the solid radical: consislem Wilh the resulLs of 68CAMIJON allli 78PAS

J. Phys. Chern. Ref. Data, Vol. 25, No.4, 1996 NIST-JANAF THERMOCHEMICAL TABLES FOR THE BROMINE OXIDES 1083

Table 6. (Continued.)

Bond Distance rCA) Vibrational Frequencies

Source Structure Br-O 0-0 Br-Bf VI V2 V3 Comments

92NOV e 2L·, 1.80902 Ab initio calculations and an extended basis set; comparable with the 1IS.69° results of 90LEV/OGD

95LEE e 2 L" 112.9° 1.865 512 180 613 Ab initio calculations-CCSD(T)

95MUE/COH elL' ' 1.8429 180 Microwave spectra for three isotopomers 112.24° BrBrO 73DIXfPAR 150° Reaction complex O-Br-Br; plausible triplet ground state at a= 180°, however, an improved approximation might change a to 150° 73PARIHER Cross-beam experiments involving collision ·of 0 atoms with Br molecules; predicts an O-Br-Br nonlinear complex with a triplet ground state 78TEVIWAL 804 <200 236 Infrared spectra of the Ar-Brr03 matrix isolated radical: the Br-Br bending mode are based on comparison with the Cl-Cl stretch and CICIO bending mode of CICIO 80VELIDUR Cross-beam scattering; stated reactive results are consistent with the long-lived triplet of the OBrBr complex as suggested by 78TEV/ WAL and 73PARIHER 82FERISMI 3A" Reactive scattering of 0 atoms with Br2; proposed existence of a shortlived OBrBr collision complex with a bent configuration and with a modest Eo of approximately 110 kJ/mol; supports the conclusion of 73PARIHER

84JAC. 804 236 Review recommended VI and V3 from Ar matrix study by 78TEV/ 9OJAC. WAL Frontier orbital theory and Lewis electronic structure theory: 94JAC proposed existence of a long-lived intermediate of a cyclic BrBrO 87LOE/AND structure 9SLEE 1.690 2.5\0 793 215 153 Ab initio calculations-CCSD(T)

Br-O 0-0 Br-O

68EDW/GRE Rate law stoichiometry; classified as BrBr02

70CLY/CRU 1.64 1.5 2.0 Electronic absorption spectrophotometry in a discharge-flow system of BrO', tran~ition-\;tat" theory: a symmetrical planar bent chain triplet species with a structure (BrOOBr) was assumed; estimated in comparison with .cZlOOCI

78TEVIWAL IR argon matrix spectroscopy; photolysis; weak bands appeared at 831.7, 830.2. and 760.3 cm -I; identified the most likely structure of Br202 as an open chain when the Br-Br bond remains intact (OBr­ BrO), and a (ErOBrO) structure formed by the insertion of an oxygen atom into the weakened Br-Br bond

8.f.EPIILAR MOVB theory: reference to this species in table but no data provided

Br20., 7.f.PAS/PAV Prepared from the thermal decomposition of Br20 I: Raman absorption and IR spectra; the vibrational spectrum of Br203 shows the presence of a BrOBr bond but it was not possible to distinguish between the two forms (OBrOBrO and BrOBr02l

76PAS/PAV c, Raman specrra: suggesred a (05r08rO) sIrucmre for 8r203: some vibrational frequencies have been assigned to specific vibrational modes

77PAS/PAV Raman spectra; sug.2:ested a svmmetric structure (OBrOBrO); some frequencies have been assigned to specific vibrational modes

87ALLJPOL 973.1-1029.6 IR spectra of a crystalline Br20, in argon matrix: not able to determine which structure (BrOBr02 or OBrOBrO) existed; the ~)TlIllIctrical structure wa~ adopted based on compari~on of Raman spectra of Br203 and Br20.j

J. Phys. Chern. Ref. Data, Vol. 25, No.4, 1996 1084 MALCOLM W. CHASE

Table 6. (Continued.)

Bond Distance rCA) Vibrational Frequencies

Source Structure Br-O 0-0 Br-O Comments 93STI Proposed anionic structure of Br+Br03 for Br203 BrZ04 73PASIPOT C 2t' or C z 861-882 205 910-919 Raman spectra at -180°C; (02BrBr02) Br204 is classified as having a dimeric structure (02Br-Br02) with a Br-Br bond 74PASIPAV. Raman spectra; suggested structure to be (02BrBr02) Raman (02BrBr02) spectra; suggested structure of the two isomers of Br204 to be 76PASIPAV (02BrBr02) and (02BrOBrO); some vibrational frequencies have (OzBrOBrO) been assigned to specific vibrational modes of the two symmetric and asymmetric isomers

77PASIP A V C 2v or C 2 Raman spectra; suggested structures (02BrBr02) and (02BrOBrO) (OzBrOBrO) for thc two isomcrs of Bl20 4 , :'IOlUC [lc4ucudt:s havt: bt:t:Il assignt:ll to specific modes of the symmetric and asymmetric isomers

92GILILEV Spectroscopic and EXAFS data on solid compound; interatomic (BrBr04) distance given Br205 77PASIPAV Based on the Raman spectra and structure of Br203 and BrZ04' an 120 5 analogous polymer structure is proposed for BrZ05

2 served the Raman spectra of the crystalline bromine dioxide dence for the A A2f-x2B 1 electronic transition. They re­ at - 180°C in a sealed tube in vacuo. There is no structural ported vO,o,o= 16178 cm-1 and approximate vibrational fre­ or vibrational information provided directly for Br02(g), al­ quencies for the excited state (VI =600 cm -1 and v2=200 though tentative assignments had been made for the crystal­ cm- I ). line dimer. Preliminary results of a microwave study of OBrO(g) by Tevault et al. [78TEV/wAL] studied the reaction of Mueller et al. [95MUEIMIL] suggested a bent structure, atomic and molecular bromine with atomic and molecular r(Br-O)= l.649 A and «OBrO)= 114.4°. They also ob­ oxygen in argon matrices (photolysis of bromine and ozone served the V2 and 2V2 states, but the relative intensities were containing matrices). Several bromine oxygen compounds not measured. Results are consistent with a V2 value of ap­ were stated to have been formed and identified by infrared proximately 300 cm -1. spectroscopy - BrO, OBrO, BrBrO, BrOBr, and (BrOh. Maier and Bothur [95MAIIBOT] studied the flash pho­ The apex angle of Br02 was calculated to be 110± 2° based tolysis of a gas mixture containing bromine, oxygen and ar­ on three facts: gon. Br02 was f9rmed by rhe matrix irradiation of BrOO. 1. The proper identification of the symmetric stretching The IR absorptio~ of two isomers (081 BrO and 0 79BrO) was frequency V3 to be 852 cm -1, observed at three different concentration ratios of Br21 18 2. Observed frequency shifts with the use of 0 3 , and 02/Ar and values for VI ~nd V3 were assigned. 3. Splitting due to the naturally occurring bromine iso­ Pfiugmacher et al. [51PFL/SCH] experimentally measured topes (79Br and 8IBr). the enthalpy of formation of Br02 (cr). The value reported wa~ -12.5-'-.0.7 kL:ul whidl, ill fUL:l, rdt:rs lu lht: ut:L:umpu­ Bowmaker and tloyd [~~tlUW/tlUY] assumed the BrU2 geometry as suggested by [73BYB/SPA] in performing an sition heat. The formation reaction is the reverse of what was SCF-Xa study of the bonding and nuclear quadrupole cou­ measured. Wagman et al. [68WAGIEVA], [82WAGIEVA], pling in BrOz . Butkovskaya et ai. [83BUTIMOR], in their in their reviews. assumed that the measured value referred to the energy of the reaction (not the enthalpy) and corrected kinetic studies, proposed a C2v structure with a bond angle of I 18° and a bond distance of 2.9 A by analogy with OCIO. the value for a ~(pv) term, adjusted the value from -45°C This series was detected by modulated beam mass spectrom­ to 25°C, thus resulting in a value of 11.6 kcallmol for the etry. Magnetic and electric field beam focusing revealed that enthalpy of formation of Br02(cr). Glushko and Medvedev OBrO is a paramagnetic molecule with a C2v symmetry. (1965) adopted 12.5 kcallmol as the enthalpy of formation. Jacox [84JACl [90JAC], [94JAC], in her reviews, recom­ Cottrell [54COT] reported D(O-BrO) ~ 70± 10 kcal/mol. mended a v3=852 cm- 1 asymmetric stretch value, based on (This converts to ~fH=87.3 kJ/mol.) This value was based the work of [78TEV!W ALl on the enthalpy of formation of Br02(cr) reported by Rattigan et al. [94RAT/JON] observed a visible absorp­ [51PFL/SCH] and Do(BrO)=2.25 eV or 50 kcallmol. Cot­ tion spectrum arising from OBrO in the bromine sensitized trell expressed doubt as to the validity of this value based on decomposition of ozone. The authors provided spectral evi- comparison with CI02 . The enthalpy of dissociation re-

J. Phys. Chern. Ref. Data, Vol. 25, No.4, 1996 NIST -JANAF THERMOCHEMICAL TABLES FOR THE BROMINE OXIDES 1085 ported by [66VED/GUR] is ilH(298) ;?! 70 kcallmol for the gon. BrOO was produced by this process. The IR absorption IS 16 reaction Br02-+ BrO+O. This is an estimated value based on of three isomers (Br160 O, BrlSO 0, and Br1602) was ob­ the work by Cottrell (1954). In contrast Huie [95HUIILAS] served and values for V I were assigned. has estimated the ethalpy of formation of OBrO(g) in the A number of authors have cited an enthalpy of formation following manner. According to Stanbury [89STAN], the en­ [81SANIWAT],[88TOOIBRU] or a bond dissociation en­ thalpy of formation of OBrO in the gas phase can be esti­ ergy [70CLY/CRU], [83BUTIMOR], [95HUIILAS] for BrOO. However, all of these studies are based on the work mated from the value of il GO = 144 kJ mol- 1 in the aqueous phase by comparison with the gas and aqueous phase values by Blake et al. [70BLAlBRO]. for OCIO~ Taking il GO = 120.5 kJ mol- 1 for OCIO(g) and Ip and Bums [69IPIBUR] determined the recombination aGo= 117.6 kJ mol- 1 for OCIO(aq) [Wagman, 1968] and rate constants of bromine atoms in the presence of six dif­ assuming the same ratio applies for OBrO, we obtain ferent third bodies (helium, neon, argon, krypton, oxygen ilGo= 148.0 kJ mol- I for OBrO(g) and ilfHo= 130 and nitrogen) over the temperature range of 300 and 1273 K. kJ mol-I. The authors refer to two earlier studies: Rabinowitch and Wood [36RABIWOO] and Strong et al. [57STRlCHI]. Based on these data, Blake et ai. [70BLAlBRO] calculated 5.3. Br02 (BrOO) interaction potentials between atomic bromine, oxygen and an inert third body (such as a rare gas). A value was given All references dealing with BrOO are listed in the follow­ for Br-02' BrOO was thought to be unstable with a bond ing four categories. This listing is somewhat arbitrary but is energy (Br-OO) of approximately 1 kcallmol which trans­ intended to give the reader a purview of the data. The struc­ lated to an enthalpy of formation of 108 kJ/mol. ture and vibrational frequencies of this molecule are summa­ rized in Table 6. 5.4. Br03 I. Formation as an intermediate in kinetic schemes - [69IPIBUR], [70BLAlBRO], [70CLY/CRU], The articles pertaining to Br03 may be classified as fol­ [77CLY/CUR], [8OJAFIMAI], [81SANIWAT], lows. [83BUTIMOR], [86SAN], [88TOOIBRU], [93MAUI 1. Formation/preparation - WAH] [28LEW/SCH], [29LEW/SCH], [29LEW/SCH2], 2. Reviews - [30LEW/SCH], [38CSHlWIE], [39SCHlWIE], [77CL Y/CUR], [84BURILAW], [84JAC], [90JAC], [40MUN/SPI], [53PFL], [55PFL], [55PFL/RAB], [94JAC] [58ARV/AYM], [59ARV/AYM], [59PFL], [59SCH], 3. Spectroscopy/structure - [60BRI/MAT], [62GUEIPAN], [74S0L/KEI], [70CLY/CRUl, f78TEV/SMA 1, r79MICIPAY1, r82MuKlKHIl [83BUTIMOR], [95MAIIBOT] 2. Radiolysis - 4. Enthalpy of formationl dissociation energy - [60MATIDOR], [62BOY/GRA], [70AMIITRE], [69IP/BUR], [70BLAlBRO], [70CL Y/CRU], [70BEG/SUB], [71SERIZAK] [81SANIWAT], [83BUTIMOR], [88TOOIBRU], 3. Spt::l:lruSl:upY!SllUl:lUH: - [95HUIILAS] [56VEN/SUNJ, [63VEN/RAJ], [64RAO/SAN]. Butkovskaya et al. [83BUTIMOR], in their kinetic studies, [72RAO], [77LEEIBEN], [78THIIMOH], [84SASI proposed a C s structure with a bond angle Br-O--O"- 1200 RAO]' [85BYB], [86UMAlRAM] and bond distances of r(Br-0)=2 A and r(O-O)= 1.5 A. 4. EPR [83BUTIMOR] referred to the [70CLY/CRU] study to aid in [70BEG/SUB], [71SERlZAK], [72RAO/SYM], estimating a structure for BrOO. [74BYB/KIR], [85BYB] Michael and Payne [79MIC/PA Y] discussed a calcula­ 5. Review - [34BRAJ, [60GEO], [63SCH/BRA], [80KOL], tional approach (BEBO) in which they detemlined VI =872 [84JAC] em -I. Although this method was stated to be indeterminate for the bending frequency. the a.uthors did suggest that a 6. Enthalpy of formation - [4RFAR/KLEJ value of V2 = 100 cm - I was consistent with their kinetic data Early work refers to the formation in the condensed phase in the region of 200-360 K. of the trioxide (or its dimer, the hexoxide). Jacox [84JAC]. [90JAC], [94JAC] reviewed the spectro­ There is no confirmatory information as to the proper scopic properties of BrOO: the sole reference being the spec­ characterization. There are many articles dealing with the troscopic work by Tevault and Smardzewski [78TEV/SMA] formation or reaction of Br03' Pflugmacher et al. [55PFLI on the infrared spectrum of the Ar matrix isolated radical. RAB] studied the reaction of bromine with excess O2 in a Tbe 1IIea~U1elllelll PIU\ ideu all 0-0 ~tlctchillg ftequcncy of gluw uisduuge al 0 "C. Bt03 wa~ daiweu tu ue the product. 1487 cm -I. There are no gas phase studies which character­ Although the ratio was 1:3, it is not clear that the product ize this molecule. was Br03' The compound formed was claimed to decom­ Maier and Bothur f95MAIIBOTl studied the flash pho­ pose above - 70°C. Also, the method of Lewis and Schu­ tolysis of a gas mixture containing bromine, oxygen and ar- macher [29LEW ISCH], in which the reaction of bromine

J. Phys. Chern. Ref. Data, Vol. 25, No.4, 1996 1086 MALCOLM W. CHASE with ozone was claimed to produce Br30g, was reproduced calculation of atomic phase shifts (as applied to extended here with a larger excess of ozone and yielded Br03 (in the x-ray absorption and fine structure in molecules and crystals) condensed phase). . predicted a Br-O bond length of 1.66 A in solution. No Arvia et al. [59ARV/A YM] studied the thermal reaction other information of Br03 was provided. between bromine and ozone. Under different conditions, they There is no reported information as to the experimental observed Br20S and Br30g. The authors specifically stated determination of the enthalpy of formation of this radical. that Br03 or Br206 was not observed, contrary to the result There is a calculated value reported by [48FARlKLE] of of Pftugmacher. Pftugmacher [59PFL] and Schumacher +23 kcallmol. Although the authors, Farkas and Klein,

[59SCH] responded to this article and further discussed pos­ stated that they calculated the enthalpy of formation of Br03 sible interpretations of the results. the formula given was BrO; . Solomon and Keith [74S0LlKEI] made several attempts to prepare Br02, including the glow-discharge method of [37SCHlSCH]. The techniques used produced bromine ox­ 5.5. Br04 ides of variable composition including Br02, Br03' and It is important to note that this oxide has not been isolated. Br02.71 (very close to Br30g). There is no thermodynamic information and no spectro EPR studies often provide information as to the structure scopic information. of the molecule and the nature of the electronic ground state. Br04 has been proposed to be formed: In the case of Br03, the EPR studies were consistent with a (1) As a weak adduct, RrO.O , in thp di"proportionation C symmetry but thele wa:s 11U lldi11itive evillellce LO con­ J 3v of BrO [90TURlBIR] . firm this. (2) In the 60Co y-irradiation of an acidic aqueous glass Br03 was produced by the y-radiolysis of KBr03 at 77 K containing perbromate ions [75GIN/SYM] [70BEG/SUB]. From the EPR measurements of Br03 and an (3) In the X-irradiatIon.ot .K.Hr04 crystalS [71BYB] assumed C 3v symmetry, they calculated the bond angle to be 0 (4) As a complex (Br02·02) during the X-irradiation of 114 • The structure was distorted in the crystalline environ­ KBr04 (calculational model and EPR study) [75DAL/ ment. The authors stated that the radical must be distorted LIN] from C 3v symmetry presumably because of an asymmetric (5) By the X-irradiation of KCI0 single crystals doped environment of the potassium ions around the oxygen atoms 4 with KBr04 [85BJEIBYB] of Br03' Similar results were reported in 1985 by Byberg (6) During the X-irradiation of KBr04 single crystals in [85BYB], in which the author reported that the Br03 radical which a weakly bound complex (Br02' 202) was had C 3v symmetry but some distortion might occur due to formed which decayed to Br04 [75BYBILIN]. the nature of the host crystal. He discussed a bond angle of 112° and a bond length of 1.57 A. The other studies provide no additional information. 5.6. Br20 (BrOBr) The spectroscopic articles for the gas phase radical in­ volved force field calculations of pyramidal XY3 type mol­ All references dealing with Br20 are listed in the follow­ ecules [56YEN/SUN, 63YEN/RAJ, 64RAO/SAN, 72RAO, ing six categories. Of prime interest are the spectroscopic 78THIIMOH]. Contrary to the implications of these five ar­ studies and the ep.thalpy of .formation calculation. The struc­ ticles, there was no observed structural information nor was ture and vibrational frequencies of this molecule are summa­ there any observed vibrational information. Upon examina­ rized in Table 6. Br20 has been experimentally studied in tion of the earlier literature cited by these authors, vibrational condensed media and in the gas phase. frequency information was found for BrO~ in a crystalline 1. Preparation/decomposition environment. Two of the four vibrational frequencies [30ZIN/RIE], [31LEWIFEI], [35BRE/SCH], IIlUlched exaclly Wilh those reponed for Br03 . These ar­ [36BRE/SCH], [38SCHIWIE], [j9SCHIWIE]. ticles have assumed a pyramidal structure with an O-Br-O [40MUN/SPI], [6 1GUE/GOU], [62GUE/PAN] angle of 89'J (the same angle was used for the chlorine, bro­ 2. Review - mine. and iodine trioxides): a bond distance Br-O of 1.68 A [:14RRA], [AOGFO], [A~SrHfRRAl [72RRT]. (from Badger's rule L and vibrational frequencies (in cm -I) [84BURlLAW], [84JAC], [9OJAC], [94JAC] of 1'1=442 [AI]. v::=800 [A::]. v3=350 [E], and v-l=828 3. Reaction - [El [47KLAlBOL], [53KAN], [69JEN/ZIE], [72BUN], T\vo additional studies provide insight into the structure of [72BUB2], [760DYINEC], [79MIT], [89FLE/SWA],

BrO.,. Electric field gradients at the halogen site in X03 and [87SW AlFLE] , [94DNEIELI], [95HEU/HAN] XO~ - radicals (X =CL Br), formed by the y-irradiation of 4. Spectroscopy/structure - single crystals of NaCIO.<. KCIO-,. KBrO.< and (In solution) -[54ANB/DOS] Sr(BrO ..~)~·H20 have been evaluated by MO calculations us­ (In crystal) [68CAMIJON], [77PASIPA V], ing the CNDO/2 method. The symmetry of the XO" radicals [90LEY/OGD] \\as aS~llll1ed h) be that of Xo.~ ions \\hich haw C,\ sym­ (In matrix) [78TEVIWAL]. [87ALLlPOL]. metry [86l:\IA/RA\I]. Lee anu Beni [77LEE/BE~]. in their [90LEY/OGD]

J. Phys. Chern. Ref. Data, Vol. 25, No.4, 1996 NIST -JANAF THERMOCHEMICAL TABLES FOR THE BROMINE OXIDES 1087

(In gas) - [73PARlHER], [84BOL/BAL], [84EPII with large reaction yield and no activation energy, but the LAR], [92NOV], [9SLEE], [9SMUE/COH], [9S0RLI known, stable B[20 molecule does not correlate with the BUR] reactants.' , 6. Enthalpy of formation - The IR spectra of the solid was most satisfactorily ex­ [92NOV], [9SLEE], [9S0RLIBUR], [9STHOIMON] plained [68CAM/JON] in terms of a bent triatomic molecule I S. Physical properties (viscosity, thermal conductivity) - with C 2v symmetry and a vI=504 cm- , v:;=197 em-I, and I [62SVE] v3=S87 cm- . The assumed bond angle was 113°. 6. Misclassified (should be BrO) - Pascal et al. [77PASIPAV] assumed that BrzO was formed [ 66CARILEV] from the decomposition of Br203' The authors observed the The earliest studies dealing with the preparation of Br20 symmetric stretch of Br20 to be 504 cm -I, the asymmetric I are based on work by [30ZIN/RIE], [31LEWIFEI], and stretch, 590 em -I, and assumed the bend to be 197 cm- . [3SBRE/SCH]. The Raman analysis of Br20 corroborated the previous in­ In a review article. Brady [34BRA] stated that Zintl and frared work by Campbell et al. In a later study, Pascal I I Rienacker [30ZINIRIE] obtained small quantities of a vola­ [78PAS] reported vI=S06 cm- and v3=592 cm- values. tile OXIde. perhaps Hr20, by two methods; (l) by passing The results of Tevault et al. [78TEVIW AL] arc in contrast bromine vapor over a specially prepared HgO at SO-60 °C, to those observed by Campbell et af. [68CAM/JON]. It ap­ t and (2) by mixing bromine vapor with ozone under reduced pears that these authors assigned v I a value of 526.1 cm- pressure at O°c. A subsequent study by Brenschede and and they implied that the assignments of VI and v3 by Schumacher [3SBRE/SCH] examined the reaction between [68CAM/JON] are reversed. Using Tevault's value of V3' a HgO and bromine in a carbon tetrachloride solution. The minimum value of 87° was calculated for the bond angle. method of preparation is given, as well as the self decompo­ Bolander and Baldeschwieler [84BOL/BAL] examined the sitIon and the reactIon WIth carbon tetrachlorIde In lIght [the dependence of the extellded x-ray dU:'lOljJlivlI fllle :'lllUclUle, same reaction occurred in dark in a few days]. The decom­ amplitude, and phase on thermally excited vibrations. The model system the authors studied was Br20. They assumed position in light was presumed to be Br20----+Br2+ 11202 and Br20+CCI4----+COCI2+Br::>+CI2' A subsequent study by the the symmetric stretch and bend occurred at 250 and 245 same authors [36BRE/SCH] examined the same formation em -I in the linear structure, while the asymmetric stretch . reaction. In addition, they studied the extinction curve of occurred at 800 cm -I. These assumed frequencies were used

Br::p dissolved in CCl4 and the thermal and photochemical to calculate force constants which were then assumed to be decomposItion. independent of the geometry of the molecule. No experimen­ Schwarz and Wiele [38SCHIWIE] studied the thermal de­ tal data were referred to and no preferred structure was rec­ composition of Br02' In addition to the formation of the ommended. This article provided estimates of the vibrational elements. the authors also detected a white oxide which they frequencies as a function of bond angles. presumed was Br207 or Br206 and a dark-brown oxide, Epiotis et al. [84EPIILAR]. using a MOVB theory. re­ Br:;O. Schwarz and Wiele [39SCHIWIE] continued their ferred to Br]O in a table but provided no information. study of the thermal decomposition of Br02' Their study Allen ef al. [87 ALLIPOL] studied the IR spectra of matrix showed that BrO:; is completely stable at ~40 °C but that isolated Br20 and assigned v3 to be 623.4 cm J and VI to be decomposition can be detected manometrically. BrO:; sub- 526.1 cm -[. The authors referred to a bond angle of 113 ° or - limes with extensive decomposition. melting in dry air at 87° based on the V3 isotopic shift information. approximately -17.5°C Br:;O is stable at 40°C. Again Levason et al. [90LEV/OGD] studied Br:?O (cr) by infra­ Br207 was suggested as one of the decomposition products red and UV -VIS spectroscopy and bromine K -edge extended of Br02' x-ray absorption fine structure (EXFAS). This is the first Le\\'is and Feitknecht [31 LEW/FE I]. in examining the de­ definitive structural analysis study for the bromine oxides composition of ozone in the presence of bromine. detected (Br20~ was definitively analyzed at a later date by others). the formation of a number of oxides. but not Br20. The The authors' results are consistent with the IR spectra of specitic oxide formed was not identified. The remaining Br20 obtained by Campbell et al. [68CAM/JON). the 18 0 studie,; dealing with the formation of Br~O are based on results which demonstrated that ~;olid Br~O is molecular. and \'ariation~ of these procedures, All studies inyolving the for­ with experimenrs by Pascal [78PAS] who reported lit =506 mation. preparation and decomposition of Br:;O are reviewed em ~ I and /);, = 592 cm ~ J. The data were consistent with by [34BRA]. [63SCH/BRA] and [72BRI]. as well as in the C'2c symmetry and a bond angle (Br-O-Br) of ! 12::1::::2° and Gmelin series discussed in the Introduction. bond distance 1'(81'-0)= 1.85 A. Anthar and DustrovsKY [5.-J.AI\'T/DOS] measured the ultra­ With the aid of ab illitio calculations and an extended \iokt absorption spectra of Br20 in CCl-1.' A strong absorp­ basis set. Novak [92NOV] calculated 3 C:;.\ geometry with tion band wa:'i obscrycd at 2800 A (35714 em ·-1), r!Dr-O)= 1.80902 A and

J. Phys, Chern. Ref. Data, Vol. 25, No.4, 1996 1088 MALCOLM W. CHASE

I mended an al symmetric stretch of 526.1 cm- (Ar) based on OCICI with a 3n sym1!letry when colinear and 3A" the studies by [78TEV/W AL, 87 ALLIPOL], and a V3 asym­ symmetry when bent. Browett et al. [81BROIHOB] I metric stretch of 623.4 cm- (Ar) based on the work by referred to the analogous 0-X-X study as described [90LEV/OGD]. Jacox did not report a value for V2' by [78TEV/wAL] and [73PARlHER] Lee [95LEE], using ab initio techniques, calculated the (5) The vibrational frequency information (vI' V3) was equilibrium structure and harmonic vibrational frequencies reviewed by Jacox [84JAC], [9OJAC], [94JAC] and of Br20. The results suggested a C 2v symmetry with a bond angle of 112.9° and a bond distance of 1.865 A. was based on the data reported by [78TEV/wAL] Mueller and Cohen [95MUE/COH], from the microwave (6) [93SCH/ABD] used Fourier transform infrared (FTIR) spectra of three isotopomers of BrOBr(g), determined techniques to study BrBrO in an argon matrix; their ro = 1.8429 A and a bond angle of 112.24°. Their study im­ observations supported the conclusions of Tevault I plied v2=180±5 cm- . et at. [78TEV/wAL] . Novak [92NOV] estimated the enthalpy of formation, (7) Burdett et al. [84BURlLAW], in a review, discussed AfHO(Br20, 0 K)=83± 8 kJ/mol from a sum of bond enthal­ the stability and spectroscopic properties of BrBrO but pies that were deduced from the data of H)O and HOBr. The referred back to the work of [78TEV/w AL ] as the enthalpy of formation corresponds to AatHO(O K)=399.6 kJI only source of information mol or an average bond dissociation energy of roughly 200 (8) Lee [95LEE], using ab initio techniques, calculated the kJ/mo!. The author did not specify the temperature; we as­ equilibrium structure and harmonic vibrational fre­ sume T/K -0. quencies of BrBrO. Orlando and Burkholder [950RLIBUR] recorded the UVI visible absorption spectra and observed maxima near 200 nm In examining cross beam experiments involving the colli­ and 314 nm. They also determined the equilibrium constant sion of ° atoms with bromine molecules. Parrish and co­ for the reaction Br20+H20-+2HOBr, K=0.02. Using auxil­ workers [73DIXlPAR, 73PARlHER] proposed the existence iary data, [950RLIBUR] derived AfH(Br20, 298 K) of an asymmetric OBrBr complex with the possibility of a = 138 kJ/mol. rather substantial bond angle, 150°C. However, neither of Thorn et al. [95THOIMON] quoted the enthalpy of forma­ the two 1973 studies [73DIXlPAR, 73PARlHER] provided tion value derived by [950RLIBUR] to encompass the range definitive structural information. The kinetic studies sug­ of 113-159 kJ/mol. From a study of the photoionization ef­ gested a triplet electronic ground state. ficiency spectrum of Br20, along with the ionization energy Tevault et al. [78TEV/wAL] studied the reaction of and the appearance energy of BrO+, the authors derived atomic and molecular bromine with atomic and molecular ArH(BrzO, 298 K)=107.1 kllmol and AfH(Br20, 0 K) = 124.1 kJ/mol. The uncertainty was estimated to be ± 3.5 oxygen in argon matrices (photolysis of bromine and ozone kJ/mol. containing matrices). Several bromine oxygen compounds Lee [95LEE], using the CCSD(T) electron correlation were stated to have been formed and identified by infrared method in conjunction with the basis set of triple zeta double spectroscopy-BrO, OBrO, BrBrO, BrOBr. and (BrOh. The polarized (TZ2P) quality, calculated the enthalpy of forma­ authors observed the spectra of BrBrO in a photolyzed tion of Br20. The author reported a value of 33 kcaVmol at 0 Ar-Br2-01 matrix. The a~signments were assumed to be K (138 kJ/mo!). vl=804 C~-I (B~-O stretch), v3=236 cm- I (Br-Br stretch) and the V2 value (the bending mode) was expected to be 5.7. Br20 (BrBrO) below 200 cm -I. Veltman et al. [80VELIDUR] stated that reactive scatter­ There are no gas phase spectroscopic studies on this mol­ ing results were consistent with the long-lived triplet of the ecule. All experimental work is in the condensed phase???: OBrBr configuration suggested by 178TEV/wALJ. pure solid and isolated ·in an argon matrix. The reviews by Fernie et af. [82FERISMI] proposed the existence of a Jacox [84lAC]. [90JAC], [94JAC] summarized these struc­ short-lived OBrBr collision complex with a bent configura­ tural and spectroscopic studies in which two of the three tion and 3 A" symmetry with a modest well of an Eo approxi­ vibrations have been observed. The structure and vibrational frequencies of this molecule are summarized in Table 6. mately 110 kllmo!. There are numerous articles which provide specific spec­ Loewenstein and Anderson [87LOEI AND] proposed the troscopic information: existence of a long-lived intermediate of a cyclic BrBrO structure. ( 1 ) Reaction complex OBrBr follows the 0+ Br2 reaction - lacox [84JAC], [90JAC]. [94JAC], in her reviews, recom­ [73DIX/PAR]. [73PARIHER] (2) Infrared spectra in an argon matrix [7STEVIWAL] mended an a' BrO stretch value, in argon matrix, of 804 (3) Structure in an argon matrix [SOVELIDUR], [S2FERI cm -I and a BrBr stretch value, in argon matrix, of 236 I SMI]. [87LOE/AND] cm- , based on the study by [78TEVIWAL]. Lee [95LEE], (4) Reactive scattering of oxygen atoms with chlorine using ab initio techniques, calculated an enthalpy of forma­ molecules: observed results which are consistent with tion at 0 K of 47.4 kcallmol 098.3 kJ/mol).

J. Phys. Chern. Ref. Data, Vol. 25, No.4, 1996 NIST -JANAF THERMOCHEMICAL TABLES FOR THE BROMINE OXIDES 1089

[74PASIPAV], [76PASIPAV), [77PASIPAV], [94LEO/SEP] This oxide has been proposed as an activated complex to 3. Comment/formation without characterization - aid in the description of kinetic processes. Although the m~­ [87ALLIPOL] jority of experimental studies whic.h refer to Br202 ~ere III 4. Patent (lubricants) - aqueous solutions, there were some gas phase studIes. In [84STE] addition, there were two spectroscopic studies in which an absorption was attributed to Br202' Tevault et al. [78TEVI The status of the characterization of solid Br203 is best WAL] tentatively identified a molecule as (BrOh through summarized by statements provided by Allen et al. [87 ALLI oxygen-i8 isotopic enrichment experiments in argon matri­ POL]: "There has also been considerable work on the vibra­ ces. They suggested that the most likely structures were an tional spectra of the solid higher oxides of bromine (Br203, open chain such as OBr-BrO and BrOBrO. Mauldin et al. Br204), but structural conclusions had to be somewhat ten­ [93MAU/wAH), in their study of the self-reaction of the tative." Pascal et al. [74PASIPAV) prepared Br203 by the BrO radical, attributed an absorption structure to Br202, but thermal decomposition of Br204' The authors stated that the assumed a Br-O-O-Br structure. vibrational spectrum of Br203 shows the presence of a Epiolis et al. [84EPIILAS] listed this species in tables BrOBr bond, but that it was not possible to distinguish be­ (with many related molecules), but there were no structural tween structural possibilities: OBrOBrO and BrOBr02. data provided. The article implied that calculations could Chemical analysis established the stoichiometry. Br203 was have been made on this species, but there was absolutely no said to be a stable intermediate in the decomposition of mention of this species in their discussion. Br204 to Br20. A subsequent study [76PASIPAV], using Ra­ The pertinent articles may be grouped as follows: man spectra, indicated that the structure was OBrOBrO. At a conference, these same authors [77PASIP A V] summarized 1. Proposed intermediate in aqueous solution - their work by discussing the synthesis of the two isomers of [30BRA], [34SKR], [52EDW], [58SIG], [68BUKI Br204, Br203, and Br20 in a Raman tube and the spectra DAI), [68EDWfGRE), [72FIEfKOR], [73S0KJ obtained at 93 K. The stepwise decomposition of Br204 to DOR], [76HERfSCH], [78ROV/ZHA], [79NOSI Br20 was presented and vibrational frequencies assigned. In BOD], [86THO] summary, analysis of the vibrational spectra of the crystal­ 2. Proposed as intermediate in gas phase reaction sys- line phase by Pascal et al. [76PASIPAV, 77PASIPAV] of the terns - various possible isomers of Br203 and Br204, suggested that [70BROIBUR], (70CL YICRU], [80JAFIMAI], Br203 has the structure (OBrOBrO) and that the two Br204 [81SANIWAT], [83BUTIMOR], [86SAN], [90TURI isomers have the structure (02BrBr02) and (02BrOBrO). BIR], [93MAUIW AH] Leopold and Seppelt [94LEO/SEP] stated that because of 3. Proposed structure - thp. similarity of Raman spectra, the BrZ03 identified by l30BRAj: BrOOBr or OBrBrO (possible) [74PASIPAV] is probably identical with the Br203 investi­ [52EDW]: Donor-acceptor intermediate BrBr02 gated by the crystal structure analysis of [93KUS/SEP] (see [66SPRJPIM]: Calculation, BrOOBr (staggered or Sec. 5.10). trapezoidal) Allcll et ul. [87ALLIPOL] ~tuuieu the comlensa[ion of [68EDW IGRE]: BrBr02 03/Ar and Brz/Ar mixtures. TheIR spectrum was interpreted [70CLY/CRU]: Symmetric planar bent BrOOBr to· suggest the formation of a Brzl03 complex. However, the (120°) structure could not be unambiguously determined. [73S0KIDOR]: BrOOBr [78TEVIW AL]: Possibly OBr-BrO or BrOBrO [80JAFIMAI]: Possibly staggered or trapezoidal (Br-O-O-Br) 5.10. BrOBr02 (Br+BrOi) [SlSANIWAT]: Trapezoidal (Br-O-O-Br) Kuschel and Seppelt [93KUSISEP, 93STI] prepared [S6THO]: BrOOBr Br203 by the reaction of bromine with ozone at -50 to [90TURfBIR]: BrOOBr - 60°C. The authors stated that other workers used this same [93MAUIWAH1: BrOOBr rCB.I,,;\.ion 35 yt:m:::. ag,U uul, iu <..:uutralSt, cl1ant<.:lerized the prod­ 4. Spectroscopy - uct as BrO')· the identification may have been based on im­ [78TEVIW AL], [93MAUIW AH] pure mated;1. Kuschel and Seppelt deduced the structure of the crystal (bond distances and bond angles) by the use of the EXAFS-method (extended x-ray absorption fine structure) and the Raman spectra. The citations listed in the bibliography for Br203 can be The authors compared the structural data of their classified as follows: Br+Br03 with that described by [92GILILEV] for BrBr04' 1. Dissertations (full copy not available at this time) - The comparison suggested that these products may have [66CAM], [78PAS], [83ALL] been the same. Thus, there is some question raised as to the 2. Formation with crystal characterization - existence of BrBr04'

J. Phys. Chern. Ref. Data, Vol. 25, No.4, 1996 1090 MALCOLM W. CHASE

prepared two isomers of Br204' These authors observed a slow reaction between ozone and Br203' The asymmetric There is no gas phase or thermodynamic information on isomer [02BrOBrO] formed was not isolated and rapidly this molecule, however, some crystalline data (structure and transformed to the symmetric isomer [O]BrBrO]). An analy­ vibrational frequencies) are available. Of the eight articles, sis of the vibrational spectra of the various possible isomers the studies can be grouped as follows: of Br203 and Br]04 suggested that Br203 has the structure 1. Formation and characterization - (OBrOBrO) and that the two Br20-l- isomers have the struc­ [73PASIPOT], [74PAS/PAV], [76PASIPAV], ture (0]BrBr02) and (02BrOBrO). Some tentative spectral [77PAS/PAV], [87ALLIPOL], [94LEO/SEP] assignments have been made. [94LEO/SEP] questioned the 2. Intermediate in solution - existence of this compound. [80FOEILAN], [83FIE/RAG], [91SZAlWOJ). Pascal and Potier [73PASIPOT] interpreted the Raman 5.13. BrBr04 spectrum of the Br02 crystalline form (-180°C) in terms of Gilson et al. [92GILILEV] discussed the formation of a dimeric structure with a Br-Br bond. They specifically ruled out a chain or ring structure with bridging oxygen at­ BrBrO.1 by passing a mixture of bromine and oxygen through a discharge tube. The authors were surprised that with the oms. Tentative assignments were made for some of the ob­ hydrolysis of the yellow solid, BrO; was identified in the served frequencies. In a subsequent study [74PAS/PAV] of solution. Bromine K-edge EXFAS data on this solid detected the vibrational spectra of Br20::l, the authors discussed the vibrations which were assignable to a Br-O-Br bridge. This corresponding spectra of Br20-l- and suggested the structure is in contrast to the results of [73PASIPOT]. Three distinct to be O]BrBr02' In studying the reaction between ozone and shells were observed corresponding to terminal Br-O, bridg­ Br]03, Pascal et al. [76PASIPAV, 77PASIPAV] observed ing Br-O, and nonbonded Br-Br distances at 1.61 (2L lwu i~Ullle1::' uf B1]04' The a~yHuHelril.; isumer 1.86(2), and 3.05(3) respectively, concomitant with the [02BrOBrO], was not isolated and rapidly transformed to the A proposed structure. A Br-O-Br bridging angle of 11O± 3° symmetric isomer [02BrBr02). An analysis of the vibrational was calculated by triangulation. [94LEO/SEP] supported the spectra of the various possible isomers of Br]03 and Br204 existence of this isomer. suggested that Br203 has the structure (OBrOBrO) and that the two Br204 isomers have the structure (02BrBrO]) and (0 ]BrOBrO). Some tentative spectral assignments have been made. [94LEO/SEP] questioned the existence of this com~ Of the 13 articles, the studies can be classified as follows: pound. Allen et al. [87 ALL/POL] mentioned the formation and 1. Patent (cellulose esterification) - characterization of Br20-l- but did not perform any additional [47PRA] work on this species. 2. Preparation - The dimerization of BrO] to Br]O-l- was proposed to ex-. [39SCHIWIE], [58ARV/A YM], [59ARY/A YM]. plain aqueous reaction kinetics: [59PFL], [59SCH] 3. Review - (1) The Belousov-Zhabotinsky-system-(HBr02)/BrO; re­ [63SCH/,J3RA] action [80FOEILAN], 4. Formation with characterization - (2) The pulse radiolysis of the bromine dioxide radical and f]6PAS/PAV21, f]7PASIPAVl, r94LEO/SEPl hexacyanoferrate (4-), manganese (II), phenoxide ion, 5. Misclassified (really deal with BrO) - or phenol [83FIE/RAG], and [88BAR/BOT] and [88COS/TEN], and (3) The pulse radiolysis of the hexacyanoferrate (II)­ 6. Archeology/vitrified slag (uncharacterized) - hrnm;ltf' cy:1nirlf' I;Yl;tf'm in :1C!11f'()11I; f'thylf'nf' !?lyC'()l [88FLE/SWA] and [90HARlWHI]. [91 SZAIWOJ]. Arvia et al. [58ARV/A YM, 59ARV/A YM] studied the 5.12. 02BrOBrO thermal reaction between bromine and ozone. Under differ­ ent conditions, they observed Dr]OS and DrJOs. The authors There is no gas phase or thermodynamic information on specifically stated that BrO" or Br]06 was not observed, con­ this molecule, however, some crystalline data (structure and trary to the result of Pftugmacher. Pftugmacher [59PFL] and vibrational frequencies) are available. All three articles can Schumacher [59SCH] responded to this article and further be classified as formation and characterization: [7 4P AS/ discussed possible interpretations of the results. These stud­ PAY]. [76PAS/PAV] and [77PAS/PAY]. ies do not conclusively suggest the existence of Br20S . In attempting to study Br]O, Pascal et at. have examined Pascal et al. [76PAS/PA Y2] recorded the Raman spectra the decomposition of Br20-1- and the formation of an interme­ of the white solid Br20". The authors deduced that the struc­ diate Br20~. In the analysis of the vibrational spectra of ture (0]BrOBr02) was a symmetric, polymeric structure Br20., ' [7 -l-P AS/PA V] discussed the corresponding spectra of similar to I20 5 . Comparison of the observed Raman spectra Br20-l- and suggested the structure to be 02BrBr02' Subse­ with that known for the ions bromite, bromate and perbro­ quent studies by Pascal et al. [76PAS/PAY, 77PAS/PAY] mate resulted in the identification of vibrations which were

J. Phys. Chern. Ref. Data, Vol. 25, No.4, 1996 NIST -JANAF THERMOCHEMICAL TABLES FOR THE BROMINE OXIDES 1091 attributed to a bromine-terminal oxygen and a -bridging oxy­ composition of Br02' In addition to the formation of the gen. Additional assignments were presented by the authors to elements, the authors also detected a white oxide which they justify their selection of the structure. In a later study, presumed was Br207 or Br206 and a dark-brown oxide, [77PASIP A V] suggested that in the reaction of ozone with Br:zO. Schwarz and Wiele [39SCHlWIE] continued their bromine, whenever Br:z05 was form~d, it was always mixed study of the thermal decomposition of Br02' Their study with Br203 or Br204' The authors continued to propose a showed that Br02 is completely stable at -40°C, but that polymeric structure (for Br205) analogous to that of 1205 . decomposition can be detected manometrically. Br02 sub­ Leopold and Seppelt [94LEO/SEP] presented a crystal limes with extensive decomposition (to Dr2), melting in dry structure analysis which characterized Br20S which crystal­ air at approximately 17.5°C. Br20 is stable at -40°C. lized with three molecule propionitrile. The structure was Again Br207 was suggested as one of the intermediate de­ depicted as 0;B~OBr02' The Raman spectra of solvate-free composition products of Br02. According to Pflugmacher Br20S was in agreement with this structure. The Raman [55 PFL, 55PFLIRAB], Br207 probably did not exist. spectra determined by [94LEO/SEP] differs from that by [76PASIPAV2].

The available information does not conclusively confirm 5.17. Br30s the existence of Br206' The nine articles listed in the bibli­ There are numerous pre-1960 studies which mention the ography refer to the preparation of the condensed phase ox­ preparation of a presumed condensed phase oxide with the ide Br~06 (or Br03)' All articles involved the reaction of composition Br30S' Although 28LEW/SCH, 29LEW/SCH, ozone with bromine, except Mungen and Spinks [40MUN/ SPI] who were actually investigating [he decomposition of 29LEW/SCH2. and 30LEW/SCH discussed the preparation of this oxide, 55PFL, 55PFL/RAB, 58ARV/AYM, and ozone. No property data have been reported. There is no gas 59ARV/AYM repeated the procedure and determined that phase information. the product was Br03 (or Br206) not Br308' No property Schwarz and Wiele [38SCHIWIE] studied the thermal de­ information is available. Based on existing information, there composition of Br02' In addition to the formation of the is no conclusive evidence that this compound exists. elements, the authors also detected a white oxide which they Of the articles published since 1975 and indexed (by CAS) presumed was Br207 or Br206 and a dark-brown oxide, to this oxide, only three (of which two are both patents) may Br20. Schwarz and Wiele [39SCHIWIE] continued their deal with Br308' The other four, in fact, deal with BrO in the study of the thermal decomposition of Br02' Their study stratosphere and troposphere, and are misclassified. showed that Br02 is completely stable at -40°C, but that All citations can be grouped into five categories. decomposition can be detected manometrically. Br02 sub­ limes with extensive decomposition, melting in dry air at 1. Patent - approximately 17.5 dc. Br20 is stable at -40°C. Again [90100] and [91BEN/GER] Br207 was suggested as one of the decomposition products 2. Misclassified as Br30S (really BrO) - of BrO:::. [89DRU/AND], [89CARlSAN], [90DOTIDAR], and Pflugmacher et aI. [55PFL. 55PFL/RAB], in studying the [9 1MOUIJAK] reaction of Br2 and O2 in a glow discharge, stated that the 3. Review - product was B,r03 (or Br206) but did not isolate the com­ [34BRA], [60GEOl [63SCHIBRA] pound. 4. Formation/preparation/decomposition - Arvia et al. [59ARV/A YM. 59ARV/A YM] studied the [28LEWISCHl [29LEWISCH],[29LEW ISCH2], thermal reaction bet\veen bromine and ozone. Under differ­ [30LEW/SCH], [55PFL], [55PFL/RAB], [58ARV/ ent conditions. they observed Br205 and Br308' The authors AYM], [59ARV/A YM], [59PFLJ. [59SCH], [74S0Ll specifically stated that Bro., or Br::06 was not observed. con­ KEI] trary to the result of Pflugmacher. Pflugmacher [59PFLJ and 5. Sensitized decomposition of ozone - Schumacher [59SCH] responded to this article and further [31LEW/FEI], [31SPil [40MUN/SPI]. discllssed possible interpretations of the results. Refer to Sec. 6. Reaction - 5.-+ on BrO" for additional information. [90BIGIBRO] When Lewis and Schumach~r [28LEW/SCH] allowed bromine and ozone to mix in a flask (no temperature was specified), a white deposit appeared on the walls on the flask. Although two articles allude to the formation of the hep­ This solid was thought to be an. oxide of bromine, later de­

toxidc [38SCH/\VIE. 30SCH/\VIE]. no definitive informa scribed as Br50 tl . Shortly after the formation of the solid, an tion is available to confirm its existence. At this time, \ve explosion destroyed the apparatus. In subsequent work by assume that such an oxide does not exist. as suggested by Lewis and Schumacher [29LEW/SCH] at low temperatures,

[55PFL 5SPFLlRAB]. - 5 to 10 0 C. an oxide of bromine was formed which had the Sch\\'arz and Wiele [38SCHIWIE] studied the thermal de- composition Br"Os and existed in two crystalline modifica-

J. Phys. Chern. Ref. Data, Vol. 25, No.4, 1996 1092 MALCOLM W. CHASE tions. Two subsequent studies by the same authors [29LEWI In the 1960 review by George [60GEO], the author stated SCH, 29LEW/SCH2] examined the thermal reaction in more that the proposal of a Br03 oxide raises doubt about the detail to observe the formation and the rate of decomposi­ authenticity of Br30S' tion. The transition temperature between the two presumed The 1963 review by Schmeisser and Brandle [63SCH/ crystalline forms was determined to be -35±3 0c. The ther­ BRA] discussed the numerous experimental studies which mal reaction between bromine and ozone was studied again led to the presumed formation of Br308' The authors also in 1930 [30LEW/SCH] to determine the kinetics of decom­ referred to other related studies which stated the product re­ position. ally was Br20S' It appears that the reaction of bromine with In a review article, Brady [34BRA] mentioned that the ozone can lead to a mixture of different bromine oxides. In method used by Lewis and Schumacher [29LEW/SCH] to addition, part of the problem may lie in the precise charac­ obtain Br308, was used by Zintl and Rienacker [30ZINIRIE] terization of the products. for the preparation of Br20 [refer to the Br20 discussion for these references]. The implication is that Br308 is not a pure, single compound. Arvia et al. [58ARV/A YM, 59ARV/AYM] studied the thermal reaction between bromine and ozone. Under differ- 6. NIST JANAF Thermochemical Tables ent conditions, they observed Br20S and Br30S' The authors specifically stated that Br03 or Br206 was not observed, con­ NIST-JANAF Thermochemical Tables for BrO(g) (Sec. tnuy tu tht: rt:sult uf Pflugllladlt:L Pflugllladlt:l [59PFL] G.l), OBIO(g) (Sec. G.2), BrOO(g) (Sec. G.3), Br03(g) (Sec. Schumacher [59SCH] responded to this article and further 6.4), BrOBr(g) (Sec. 6.5), and BrBrO(g) (Sec. 6.6) are pre­ discussed possible interpretations of the results. sented on the following pages.

J. Phys. Chern. Ref. Data, Vol. 25, No.4, 1996 Bromine Oxide (BrO) Ideal Gas Mr =95.9034 Bromine Oxide (BrO) Br101(g)

1 f);; = 19.1.'2 :t. 200 <"Ill I t:;.,IIO(O K) = 133.3 :± 2.4 kJ '0101- EnthaljJY Reference Temperature; T,; 2911.15 K Standard State Pressure; pO ; 0.1 MPa .\"(2')1-1.1:; K) o~ 2.1"2')7 ~. 0.1 J K 1'11101 I t:;. ,II"(298.15K)= 125.8:± 2.4kJ·mol- ' ---J·K-'mol-'____ kj·mol-' ____ T/I\ C; So -[Go-If(T,))fT HO-W(T,) ArW ArGO log Kr

Electronic Levels and Molecular O',nstants e~BrIhO). cm" o 0.0 0.0 [NFI'l[TE -9.(l61 133.3)5 133.305 INF[N[TE Stall' r g, ('),. (vt-apolalion of Ihe Coleman and Gaydon' data gave 17800 em .. or 213.2 kJ·mol- ' for the ground state dissociation energy. -I l 1100 3'.1.634 2X3.175 254.766 31.2S0 [ 13.493 -4.722 Assul11illg Ihl' l'xlI'apolation was high by up to 20%. they recolllmended 1.75:± 0.3 eV or 170:± 29 kJ·mol- . Durie anj Ramsay,2 from a 99.451 :::t I 1200 3 '.I.S 2'1'-. 2X6.619 257.279 35.20X 113.7K0 9X.162 -·4.273 graphical Birge .. Spoiler eXlrapolation. calculaled a dissociation energy of D~ = 19332 :± 200 cm- or 231.6 :± 2.4 kJ ·mol-I. The latter value m 1300 3<).437 2'1'-.9.779 259.659 39.156 114.(J36 96.\i50 -3.X91 leads to Ihe pn.'St'lIt adopled value for t:;. ,lr(298.15 K) for BrO(g) of 125.8 :± 2.4 kJ 'mol- I. Additional data needed for the calculations 43,(196 :IJ 1 1400 3'.1.361 292.699 261.916 114.265 \/5.S19 -3.564 prl'senled here. e.g. thennal functions for the Br(g). and Br2(ref). O(g), and 02(ref), are t"ken from the JANAF Thermxhemical Tables: 1500 3'.1.301 295.412 264.06() 47.029 114.4'>7 94.173 -3.279 3: 1600 3'.1.256 297.'.147 2f6.099 50.957 114.647 92.X[4 -3.030 o IIl'at Cap< ~ 5000 34.562 341.5X7 305.614 179.'1167 106.523 47.3XX -0.495 o 5100 34.291 342.269 306.326 I X3.310 105.M4 46.213 -0.473 a Q) 5201) 34.021 342.932 307.024 IX6.725 !OS. 143 4S.04H '-0.452 m 5300 33.755 343.S7H 307.707 190.114 104.LIH 43.900 -0.433 en ~ 540) 33.491 344.206 30X.377 193.476 103.{69 42.76S -OAI4 < 55(1) 33.232 344.X IX 309.034 I <)6.X13 102.~9X 41.646 -0.396 ~ 56(~) 32.976 345.415 309.679 2()().123 102.103 40.537 -0.37H S7(1) 32.724 203.40X I\) 345.996 310.311 101.'HS 39.445 -:-0.361 .!Jl 5HOl) 32.477 346.563 310.93[ 206.66X [()().L44 3K.367 -0.346 5')(~) 32.235 347.116 311.S40 209.903 99.S79 37.305 -0.330 z 6()(~) 31.9'.1H 347.656 312.137 213.115 9X.{90 36.256 -0.316 !' PREVIOUS _.f>. CURRENT: March J 996 (I bar .-. <0 o <0 (0 (j) Brorrine Oxide (BrO) Br101(g) ~ ..... ~ Ideal Gas Mr 111.9028 Bromine oxidE (OBrO) Br102(g) o "'0 Bromine Oxide (OBrO) = <0 :T ~ '< ~ .'>..J r(o 1\.1 "' [.j ,I) , .)~! k I" 1101 I :!1,lI0(OK)=[161,5:!:25]kJ'mol I Emh,IIlY Hcfcr('occ Temperature = 7, = 298,15 K Standard State Pressure = pO = 0.1 I\1Pa o \ ,.{ .'():-;.I.~ 1\.1 , ..) II. I' I r... '11I()1 :!1[1I"{.29X. I) K) = ! 152.0 :!: 251 kJ 'mol I ___'·K·'mol"' ______.. kJ·mol-' ____ :T c CJ) TIK c; SO -[Go-if'(T,)11T II°_II°(T,) !:i.,lI !:i.,G0 log K,

~ Lit', lroni,' Level and QuanlUnl Wl'ii!1!1 (I INfiNITE -11.395 161.500 161.500 INFINITE :0 SI,!il' C,.cm ' ,1:, 50 0<)X.X61 -Y,731 16t.299 159.420 -166.544 IO() ](IK.07K -X,020 160.57:- I 57.XO') -X2.431 ~ v'n; lI.O 150 :K3.<)56 -6,IX5 15').7')0 156.5<)6 -54.531 o 20\1 "75.11 I - 4.222 15,),010 155,64') -40.651 Q) 250 :71,X46 -2,131 15X,236 154.X9X -32,364 ,(XIO ¥ VihratiolJ; I h,'qlll'i1\'il;~ ~~:~~I !)l'g,'nl'rs,'r\'('<1 Ihc infrared sperm of BrO, in a solid argon lIlalrix. As.suming the proper identification of the antisymmetric j5'1.7XO 204.451 135.517 349.370 -4.679 strelching I', to lx' X52 (Ill '. tile apl'\ angie \\as calculated to bt.' 110::':: 2" This was close to the value observed for Ihe analogous matrix 361.10'1 210.257 135.116 354.H5K -4.634 isolated O() •. :62.409 216.065 134.707 360.357 -4.591 The rel'<.1I1;llll'nded vihrali,lI1ai frequency (1',) is tilat sugge:aed by Jacox. 10 This data is based on Ihe infrared spectra of the argon matrix :63.6X() 221.K73 134,291 365.X66 -4.550 isolated radiI al a~: stlldi,'d by Tevauit ,'I (/1." I'rl'liminary micowave sludie~ by Mueller ('{ ill.1 suggested an approximate value for V2 (300 364.925 227,6H2 133.X70 37t.3x5 -4.511 ('Ill '). The uno!l,,'rved vihratioll,tI frequellcy , v,) is estimaltd from those which describe the other halogen oxide molecules." Maier and 366.143 233.491 133.444 376.913 -4.475 36V37 239.300 133,014 3H2.451 -4.439 BOlhur." usillg flash photolvsis, trapped OBrO in a matrix allc measured VI ;)nd v, for.two isotopes. Their values for Vl are within a few wave nUlllbl'r, of the valul's dnived by Tcvaull 1'1111." 1', val lies arc of the order of79 1-799 cm '1, depending on the concentration of the pyrolized 421.792 ;6X,507 245.111 132.5XI 3X7.99X -4.406 423'<)42 :69.654 25(),'121 132.145 393.556 -4.374 mixture (Br2/0c/Ar). 424.265 :'70.77'1 256,732 131.707 399.122 -4.343 425.463 371,XX3 262.543 131.266 404.69X -4.314 Rl'ferenc('s 426.637 372.966 26K.355 130.H23 41O.2X3 -4.2x6 221-'8.1 (1<)54). [T. L. Cottrell. The Strt'll~ths of Chemical Bonds, Illlllerwor.ns. 374.030 274,167 130.377 415.H77 -4.259 'A. l'f1ugmacitt-r. R, S('Il\~'all and H. J. Rabbin, Z. 11 264. 204-8 (1951 ), 375.075 27'.1.979 I 29.'!2X 421.479 -4.234 'V, l. Vcdcnl'Yl'v. L V. C;urvirh, v, N. and Yc. L Frankevich. Bond Energies, Ionization pOlenlials and 376.101 2H5.7'!2 129.475 427.091 -4.2()<) Electroll Affinilies. Amold. London, 7'1)· j77.II0 291.605 129.01X 432.710 -4.IX6 j7H,IOI 297.4IH 12H,557 ·'R. Huic and B. Laszlo, ALlv. ChI.' Ill. Series. 43H.33K -4.163 'I), M. Stanhurry. Adv. In()!g. ('he Ill. 33, 6(; j7\!.076 303,231 12H.OX'! 443.975 -4.141 ''D, D. Wagman. W. 11. Evans. V, n, Parker, R. jKO.035 30'1,045 127.615 44'.J.620 -4.120 :;XO,97LJ 314.X59 127.U4 455.273 -4.I

0. ,/1"(0 K) = [116.1 2: 4D] kJ·mo!-1 Enthal~y Reference Temperature", T, = 298. IS K Standar' State Pressure = pO = 0.1 MPa S"(2()~.I) K)= l2~~.~ I 3\.1 K "111<11 I 0. ,11°(298.15 K) = [108.0 2: 4D] kj.mol- I ___'·K-'mol-'____ kJ·mor' ____ Tm C; So -[Go-If(T,»)1T II°-W(T,) Arll" ArGO log Kr

C .O()O .000 INFINITE -12.X51 ' 116.017 116.0H7 INFINITE Electronic Level and Quantum Weight 5(1 35.~'X2 212.021 435.344 -11.166 115.YI)7 113.639 -IIX.7IK I state E" cnl- K, 100 41.HIH 23H.630 3:'1:).YOH -'!.22X 115.4>)<) 111.569 -5H.27H ISO 45.376 256.347 303.261 -7'<)37 114.Y!1 109.743 -3H.216 ---~\I'A;i--- 0.0 [2] 2()(1 47.12H 26'!.66H 2'!3.267 -4.720 114.555 IOX.(161 -2H.223 25(1 4H.143 2XO.301 2HY.646 -2.336 114.073 106.4YI -22.250 z 2YH.15 4H.x75 2X8.H45 2HH.X45 '(XX) 10X.OX) 105.736 - IX.524 Vibr12 3~6.597 99.571 Y4.Y17 170.434 -4.23'! 3: I keti-mol I (at 298.15 K) which translated te, 12 -3.04Y o 'N. I. BlltkovskaJ,I, I. I. Mommv. V. L. Tal'rose. and E. S. Vasiliev, Chern. Phys. 79, 21 (1983). 44(l(I 5X.033 436.7X2 3~3.91O 232.636 XX.633 254.7X3 -3.025 3: () 4500 58.04() ::T I'M. E. Jacox, 1. rhys. Chem. Ref. Data. Monq~raph No.3, 461 pp. (1994). 43H.OH6 3~5.0. PREVIOUS: URRENT: Marcht

~ IN:'INITE -13.101 233.000 233.!X)0 INFINITE :0 50 33.333 20<).520 nX.271 --11.43X 132.073 233.75<) -244.206 ';ta~~tl'trollic I.t.'vtl a~~ ~~arltum Weight -<).711 235.<)n - 123.26<) g, 100 36.646 233.32<) B0.43X 130.636 ~ ISO 43.0XS 24\1.376 .HXJ.X50 -7.721 229.279 23X.97 I -X3.217 o ["Ad 0.0 [2) 200 49.535 262.667 1X<).6X4 -5.403 22X.126 242.3XI -63.303 Q) 250 55.2<)7 274..'154 lX5.471 -2.779 227.156 246.060 -51.411 Ju 29KI5 59.9<)9 2X4.509 1K4.5O\J .()()() 220.X21 250.432 -43.X75 < Vibrational Fr~qul'ncies and Degeneracies 300 1H4.S10 .tll 220.7XI 250.616 -43.636 v. em'" 48). 4()I)() X2.926 4X5.496 ~1O.7x6 2'.1X.X37 223.207 747.9X4 -<).76X "K. Venkateswarlu and S. Sundaram, Proc. PLys. Soc. (London) A69. 180(1956). 41')() X2.937 ~12.634 307.130 223.20<) 761.104 -9.697 'K. Venkateswarlu and K. V. Rajalakshmi, InJian J. Pure A)pl. Phys. I, 3~0 (1963). 42'Xl X2.946 ~14.441 315.424 223.19<) 774.223 -9.62,} 4c. G. R. Rao and C. Santhamma, Current Sci. 33(22). 677 : 1964). OX) X2.956 ~16.21(J 323.71\1 223.17X 7X7.343 -'}.564 5c. G. R. Rao. Sci. Cull. 38( 12), 522 (1972). 44I)(} X2.964 ~17.943 332.015 223.145 HOO.463 -<).503 451)() "P. Thirugnanasambandam and S. Mohan, Indian J. Phys. 51U(3), 173 (19'78). X 2.972 ~1<).641 34().312 223.104 X13.5H4 -''.1.444 71. R. Byberg, J. Chem. Phys. 83(3), 919 (1985). 4600 ~21.305 34X.609 223.053 X26.706 -'.I.3XX 470() xA. Begum, S. Subramanuan, and M. C. R. Symons. J. Chem. Soc. 6, 918(1970). 422.936 356.\lOX 222.\I'}4 X3<).X30 -9.334 4KIXl 424.537 365.207 222.926 X52.'.I55 -'.I.2X2 4<)1)() 426.107 373.506 222.X4\1 X66.0H2 -'.1.233 5(~X) 427.64X 3H I.X07 222.764 X7<).210 -'}.IX5 5100 42<).162 3<)0.107 222.670 xn.34() -<).139 521)() nO.64i1 3'.1X.4()'.1 222.565 '.105.471 -9.096 531)() B2.IO\l 4()6.710 222.451 \I I X.606 -9.053 54J)() B3.544 415.ot3 222.324 <)31.741 -9.013 55')() B4.955 423.315 222.IX5 ,}44.X79 -X.974 56JO B6.343 431.61X 222.032 \l5x.022 - X.936 57'X) B7.70X 43'.1.n2 22t.X63 <)71.165 -x'900 SiI')O -139.052 44H.226 221.67X '}X4.313 - X.X65 59'X) -140.373 456.530 221.474 '.1'.17.462 -X.X31 6OX) +41.675 464.X35 221.250 1010.617 - H.7<)X

PREviOUS: CURRENT: March 1996 (I bar

Bromine oxide (Br03) Br103(g) Bromine Oxide (BrOBr) Ideal Gas Mr = 175.8074 Bromine oxide (BrOBr) Br201(g)

1 1 1::..,,11°(0 K) = JS~ ::':: 5 kJ'mol- I::..r1/0(0 K) = 124.1 ::':: 3.5 kJ'mol- Enthalpy Reference Temperature = T,= 298.15 K Standard State Pressure = pO = 0.1 MPa 1 ,\'°(298.15 K) = 290.8 ::':: 2 J K -I'moll I::.. r1/0(298.15 K) = 107.6::':: 3.5 kJ·mol- ----I·K-'mol-'____ kj·md-' ____ TIK. c: So -[Go-H'(T,»)rr HO-W(T,) 4 rH' .irG° log Kr

Electronic Level and Quantum Weight ) .000 .000 INFINITE -12.399 124.100 t24.100 INFINITE I state E,; cm- Xi j) 34.529 217.773 4,2.252 -10.724 124.:19 118.511 -123.808 HD 38.4l!O 242.978 3>1.921 -8.894 123.,59 113.112 -59.083 XIA 0.0 15) 41.918 259.228 305.126 -6.885 122.,14 108.209 -37.682 20') 45.264 271.753 295.272 -4.704 121.193 103.675 -27.077 Vibrational Frequencies and Degeneracies 25l> 4l\.(l75 282.16ll 291.638 -2.367 119.~1l5 99.433 -20.775 z v, cm- I 29lU 5 50.168 290.823 290.823 .000 107.048 96.902 -16.977 en 30') 50.238 291.133 290.824 .()93 107.:74 96.835 -16.861 526.1 (I) 40) 53.068 306.013 292.833 5.272 76.~1l7 99.594 -13.006 180 (I) S(X) 54.685 318.044 296.711 10.667 76.061 105.277 -10.998 L 623.4 (I) 60) 55.664 328.108 301.128 16.188 77.183 110.920 -9.656 » 70') 56.293 336.739 305.614 21.788 77.417 116.524 -8.695 z Point Group: C 2v • 84 X 10- 117 g.1cm6 110') 57.397 362.466 321.946 44.572 78.;71 138.654 -6.584 ::I: 120') 57.523 367.466 325.534 50.318 78.451 144.135 -6.274 m Enthalpy of Formation 13m 57.621 372.074 328.939 56.076 78.616 149.602 -6.011 14aJ 57.700 376.347 332.174 61.842 78.:66 155.057 -5.785 :0 Thorn et al.' u.,ing experimental results fromphotoionization efficiency spectrum of Br 0 along with the ionization and appearance energy. 2 1 150') 57.763 380.330 335.254 67.615 78.900 160.501 -5.589 s:: have derived a value of the enthalpy of formation I::..rH (Br20, 0 K) = 124.1 ::':: 3.5 kJ 'mol- , which we adopt. l 160) 57.816 384.060 338.189 73.394 79.016 165.938 -5.417 o There are three other related studies leading to an enthalpy of formation. Orlando and Burkholder mea~ured the equilibrium constant for 170') 57.859 387.566 340.991 79.178 79.113 171.367 -5.265 (') the reaction: Br20+H20=2HOBr. They determined I::..,GO(298 K) = 9.70 kJ·mol-' . Using the thermal functions present~d in this table and 18m 57.896 390.875 343.671 84.966 79.:89 176.791 -5.130 l ::I: thermal functions for HOBr(g) given by JANAF,2 we calculatel::..rHO(Br20,g, 298.15) = 107.6::':: 3.5 kJ·mol- • This value supports our adopted 190') 57.927 394.006 346.239 90.757 79.142 182.212 -5.009 value. Assuming that the values Dg(CIO) and ~,lr(OCIO,g) are reasonable, we would anti~ipate the ratio of the numbers (1.52) to apply for 2(0) 57.953 396.978 348.702 96.551 79.;69 187.631 -4.900 m 1 a similar relationship between BrO(g) and BrOBr(g). This would yield a value of 114 kJ'mol- which is in good agreement with our adopted 21m 57.976 399.806 351.069 102.347 79.;69 193.049 -4.802 s:: value. Using the estimation scheme of Novak4 (in part based on ab initio calculations and an extended basis set). the enthalpy of formation 22m 57.996 402.503 353.346 I OIU 46 79.139 198.468 -4.712 (; 1 wa~ calculated tc be 83 ::':: 8 kJ'mol- at 0 K 23m 58.014 405.082 355.540 113.947 79.79 203.889 -4.630 » 24aJ 58.029 407.551 357.656 119.749 79.087 209.313 -4.556 r- Heat Capacity and Entropy • 25m 58.042 409.920 359.699 125.552 78.963 214.741 -4.4l!7 260) 58.054 -i Mueller and Cohen,S from the microw2ve spectra of three isotopomers of BrOBr(g), have determined '0 = 1.8429 A and 412.197 3&1.675 131.357 7lU07 220.175 -4.423 6 270') 58.065 414.388 3&3.587 137.163 78.61B 225.616 -4.365 » « BrOBr) = 112.24°, which we adopt. Supporti1g evidence was derived from bromine K-edge EXAFS study o(Levason et aZ. The structure 280') 58.074 416.500 3&5.439 142.970 78.400 231.064 -4.311 CD of this molecule was bent with a Br-O-Br an~le of 112 ::':: 2° and the Br-O bond length was 1.85 ::':: 0.0 I A. The bond angle is in good 290') 58.0R3 418.538 3&7.235 148.778 -4.260 7 0 78.152 236.521 r­ agreement with the value derived from matrix IR studies where a value pf 113 was estimated from isotope shifts. In comparison, Novak,4 3(0) 5R.091 420.507 368.978 154.587 77.!77 241.986 -4.213 m with the aid of ab initio calculations, determined a bond length of 1.809 A and a bond angle of 115.7°. The principal moments of inertia (in 310') 58.()98 (J) 2 19 422.412 370.671 160.396 77.!77 247.462 -4.170 g cm ) are: IA = 2.5488 X 10-.19, In'" 62.1189 X 1O-.1~, and Ie = 64.6677 X 10-. • 32m 58.104 424.257 372.317 166.206 77.154 252.947 -4.129 R 111e recommended vibrational frequencies (VI, v~) are those su;gested by Jacox. These remits are based on the infrared >pectra of the argon 330') 58.110 426'()45 373.918 172.017 76.912 258.442 -4.091 -n 6 matrix isolated radical as studied by Tevault et ~l., Allen et al. and Levason et al. A value of V2 = 197 em -I reported in the solid IR spectra 340) StU 15 427.780 375.477 I 77J!28 76.J54 263.949 -4.055 o lO s I 350') 58.120 429.464 376.996 183.640 76 .. 81 269.465 -4.022 study of Campbell et al. However, the Mueller and Cohen studr implied V2 = 180 cm- (::':: 5). Lee, II using ab hitio calculations - :0 CCSD(T) - derhed vibrational frequencies (513, 180 and 613 cm- ) which are in reasonable agreeJ11ent with our adopted values. Similar 360) 58.125 431.102 378.476 189.452 75.'9B 274.994 -3.990 -i 37m 58.129 432.694 379.920 195.265 75.407 280.532 -3.960 calculations by Lee yielded a structure in a~re~ment with our recommendations (112.9° and 1.865 A). ::I: 9 380') 58.132 434.245 381.329 201.078 75.011 286.081 -3.932 All specific studies (condensed or matrix)" 12yielded values for VI and V3 which are in reasonable agreement. Although Tevault et al. stated lo 39O'J 58.136 435.755 332.706 206.891 74.612 29.1.641 -3.906 m !'­ that the values fer VI and v, reported by Campbell et al. are reversed, this does not affe,:t the thermal functions. • 4(0) 5KI39 437.227 384.050 212.705 74.114 297.211 -3.881 CD Anthar and Dostrovskyl.1 measured the ultra,iolet absorption spectra of Br 0 in eC1 • A strong absorption band was observed at 2800 A "0 2 4 410) 58.142 438.662 3&5.365 218.519 73.818 302.791 -3.1158 :::T (35714 em-I). We assume this refers to the position of (he first excited electronic state. This state is not included in the calculations. :0 '< 42()) 58.145 440.063 3&6.651 224.334 73.427 308.380 -3.835 o ~ 43()) 58.14l! 441.432 3&7.909 230.14l! 73.042 313.979 -3.814 References 44aJ 5KI50 442.768 389.140 235.963 72.666 319.5116 -3.794 3: o IJ. J. Orlando and J. B. Burkholder, J. Phys. Chern. 99, 1143-50 (1995). 450') 58.152 444.075 390.347 241.778 72.199 325.202 -3.775 :::T Z (I) 2JANAF Thermo:hemical Tables: HOBr(g), June 1995. 460') 58.154 445.353 391.529 247.593 7l.944 330.826 -3.757 m ~ 'R. P. Thorn Jr., P. S. Monks, L. J. Stief, S.-C. Kuo, Z. Zhang and R. B. Klemm, ~rookhaven National Laboratory, BNL #62126, Ilpp. 470) 58.156 446.604 392.687 253.409 71.600 336.458 -3.739 ~ 1995); J. Phys. Chern. (1996, in press). 48()) 58.158 447.828 393.823 259.225 71.170 342.097 -3.723 :D o I. Novak, Struct. Chem. 3(6), 377-9 (1992). 49m 58.160 449.028 394.938 265.041 70,953 347.743 -3.707 50()) 58.162 450.203 396.031 270.857 70.650 353.395 -3.692 >< ~ 5H. S. P. Mueller lmd E. A. Cohen, submitted for publication in J. Phys. Chern. 510) 58.163 6 6W. Levason, J. S. Ogden, M. D. Spicer, and N". A. Young, J. Am. Chern. Soc. 112, 1019 (1990). 451.354 397.105 276.673 70.,62 359.053 -3.677 o 520') 58.165 452.4l!4 398.159 282.4R9 70.08H 364.715 -3.664 m ! 7D. Allen. M. Poliakoff, and J. J. Turner, J. rvbl. Strnct. 157, I (1987). 530) 58.166 453.592 399.194 2811.306 69.!29 370.384 -3.650 (J) -0) xM. E. Jacox. J. Phys. Chern. Ref. Data, Monograph No.3, 461 pp. (1994). 540) 58.167 454.679 400.212 294.123 69.!83 376.057 -3.638 < ~p. E. Tevault, l\. Walker, R. R. Smardzewsk, and W. B. Fox, J. Phys. Chem. 82, 2733 (1978). 550) 58.169 455.746 401.212 299.939 69.,52 381.734 -3.625 ~ C. Campbell, J. P. M. Jones, and J. J. Turner, Chern. Commun. (15). 888 (1968). 560) 58.170 456.794 402.195 305.756 69.134 387.416 -3.614 liT. J. Lee, J. Phys. Chern. 99, 15074-80 (1995). 57fJ.l 58.171 457.824 403.162 311.573 6X.930 393.102 -3.602 I\) 12J. L. Pascal, A. C. Pavia, J. Potier, IUJd A Potier, Proc. Int. Conf. Raman Spectrosc. 5th (1976), No. 210447, 120-1 (pub. 1977). 58fJ.l 58.172 458.836 404.113 317.390 68.:311 398.791 -3.591 Y' 590) 58.173 459.830 405.049 323.2011 68.:57 404.4l!2 -3.581 z 6(0) 5t\.l74 460.80l! 405.970 329.025 68.;88 410.178 -3.571 ? PREVIOUS: RRENT: March 1996 (I bar _.f:>...... CD o CD <0 CJ) Bromine oxide (BrOBr) Br201(g) ...... !=­ ..... Bromine oxide (BrBrO) Br 01(g) o "'0 Bromine Oxide (BrBrO) Ideal Gas Mr = 175.8074 2 <0 :::r OJ '< 1 ~ D.,/nO K) = [183.7 ::!: 20] kJ'mol- Enthalpy Reference Temperature = r, = 298.15 K Standard Slate Pressure = pO = 0.1 MPa I o I D.rl/"(298.IS K) = [168::!: 20) kJ'mol-' ---l·K-'mol-'____ kJ·mol- ____ :::r .'1'''(2<)8.15 K)= [312.7 -~ 21 J K '-mol (1) TfK C; So -[Go-fr(T,))fT W-W(T,) tl.rW tl.rG° log Kr

~ El<:ctrDnic L('wl and Quantum Weight o I1>FINITE -13.hx IX3.713 183.7 JJ INFINITE 5() JJ state E" Clll ' K, 463.229 -11.447 IK3.8~ 177.315 - 185.239 I{)() 356.090 -9.479 183.126 17U)47 -89.346 ~ [ 'A") 0.0 [3] 150 327.647 -7.259 182.292 165.183 -57.522 o ,{)O 317.312 -4.899 181.349 159.619 -41.68X OJ ,SO 313.543 -2.442 180.262 154.309 -32.241 iii Vibrational Frequencies and Degeneracies 29U5 5J.3X5 312.704 312.704 .()()O 16X.O()O 150.730 -26.407 I < v, cm- ~oo 51.433 312.705 .095 167.928 150.623 -26.226 £()O 53.530 314.750 5.351 137.218 151.179 -19.742 ~ 804 (I) :00 54.X6X 318.676 10.776 137.422 154.646 -16.156 I\) .!JI [ISO] () (()O 55.735 323.132 16.309 137.656 15X,069 -t3.76t 236 (l) ~oo 56.316 327.647 21.913 137.895 161.453 -12.0~ z W() 56.719 332'()4t 27.566 138.127 164.802 -10.760 \{)() 57.()()X ? Point Group: C (T= I 336.249 33.253 138.347 168.123 -9.758 Il()() 57.222 340.250 38.965 138.554 171.420 -8.954 _.f:>. Bond Distances: Br-C = Br-Br = [2.SI] A. Bond Angle: Br--Br-C = 384.677 344.044 44.696 138.747 174.698 -x'296 117 h <0 Product of the Momerts 1~/PJc= [13784.9110 X 10- ] g'cm 389.676 347.642 50.441 138.925 177.958 -7.746 <0 394.2H3 351.054 56.197 I 39'()89 18J.204 -7.281 en 39H.555 354.297 61.962 I 39.23X 184.438 -6.881 4{)2.537 357.381 67.734 139.371 187.662 -6.535 Enthalpy of Formation 360.32t 73.512 139.~6 190.877 -6.231 1'01' the four halogcn oxide species. XXO(g' Br, I, there is no experimental data related to the enthalpy of formation. Lee I 363.128 79.295 139.582 194.086 -5.964 compounds using a combination of theoretical isomeric homodesmic and detcmlined tilt' cnthalpies of formation of mary i 365.812 85.081 139.657 197.290 -5.725 isodcsmic rcaction energies. The calculated results BrBrO is less stable than BrOBr by 14.6 kcal'mol- (61.1 kJ·mol) at 36083 90.872 139.708 2()().490 -5.512 s: 2()S.IS K. 370.849 96.665 139.735 203.6X9 -5.320 » 422.01() 373.219 102.461 139.734 206.886 -5.146 I 424.707 375.498 108.259 139.704 210.085 -4.988 I1eat Capacity and Entropy 0 (') Lee.' using ah initio calculations - CCSD(T> - derived a bond angle of 113.10 and bond distances r(Br-Br) = 2.510 A and r(Br-O) = 1.690 427.285 377.694 I t4.059 139.643 213.285 -4.844 2 w 429.754 379.812 119.860 139.550 216.~8 -4.712 0 A. which we a

PREvIOUS: CURRENT: March 1996 (l bar

Bromine oxide (BrBrO) Br201(g) NIST-JANAF THERMOCHEMICAL TABLES FOR THE BROMINE OXIDES 1099

7. Conclusions Heat capacity and enthalpy are not necessary at this time. (See Table 7.1.)

Of the bromine oxides mentioned in the literature, only TABLE 7.1. Thennodynamic Properties of the Bromine Oxides. nine have been prepared (as a single crystal, or in the gas phase, or a matrix) and (at least, partially) characterized: OK 298.15 K BrO, BrBrO, BrOBr, OBrO, BrOO, Br203, 02BrBr02' AfHo AfHo Apo CO SO 02BrOBrO, and Br20S' Only early studies exist which men­ p Compound kJ mol- 1 J mol- 1 K- 1 tion Br206 and Br207; it would appear that these species do not exist. Br93 and Br04 are proposed as intermediates in BrO(g) 133.3±2,4 125.8±2,4 109.6 34.2 232.97±0.1 solutions or crystalline environments, with only an absorp­ OBrO(g) [161.5±25] [152.0±25] [155.0] 45.4 271.1±2 tion maximum as a characterization. BrOO(g) [116.1±40] [108.0±40] [105.7] [48.9] [288.8±3] Br0 (g) [233±50] [221±50] [250,4] [60] [284.5±2] Early references to Br30g are undoubtedly incorrect. Dif­ 3 BrOBr(g) 124.1±3.5 107.6±3.5 96.9 50.2 290.8±2 ficulties in the experimental determination of the true iden­ BrBrO(g) [183.7±20] [168±20] [150.7] [51.4] [312.7±2] tity and composition of the solid oxides caused difficulty for all the condensed bromine oxides in the period before 1970. Recent references to this oxide are also incorrect in the sense that they should have been indexed to the monoxide-BrO. 8. Acknowledgments Thus, at this time, there is considerable uncertainly as to the existence of this compound. Finally, even recent evidence This work was undertaken as part of a larger study to suggests that the characterization of the various isomers of provide NIST -JANAF Thermochemical Tables for as many Br204 may not be correct. halogen oxide species as possible. This particular study for In the following table, a summary of the recommended the bromine oxides was supported by the Standard Reference thermodynamic properties at ambient conditions for six bro­ Data Program at the U.S. National Institute of Standards and mine oxides are given. The brackets indicate estimated val­ Technology. The author is particularly grateful for the help ues. The recommended values contain significant uncertain­ of Sabina erisen who confirmed the completeness of the ties. In all cases, experimental enthalpy of formation data are annotated bibliographies, created the numerous tables which needed. However, due to its importance in atmospheric summarize the reported experimental studies, and obtained chemistry, the prime effort should be directed at determining copies of the pertinent articles. In addition to the anonymous experimentally the enthalpy of formation of OBrO(g). Fur­ reviewers of this article, the contribution of Stanley ther eUorts should be dIrected towards confirmmg the disso­ Abramowitz in discussions on the spectroscopic properties of ciation energy of BrO and the enthalpy of formation of BrO­ the triatomic molecules is greatly appreciated; Edward A. Br(g), and establishing the enthalpies of formation for Cohen (JPL) for providing data prior to publication and for BrOO{g), BrDrO(g) and Br03(g). Por any of the polyatomic n:vh::wing puniuw; u[ lhis anick; Hulger Mueller (JPL) [or gaseous species, except BrOBr, spectroscopic measurements reviewing portion~ .. of this .article; Cl:nd R. B. Klemm for the geometry and vibrational frequencies would greatly (Brookhaven National Lab) for information pertaining to the reduce the uncertainties in the resulting thermal functions. enthalpy of formation of BrzO as well as reviewing this ar~ Confirmation as to the existence of the various condensed ticle. The BrO calculations were performed by David Neu­ phases is needed, although this is a much lower priority. mann.

J. Phys. Chem. Ref. Data, Vol. 25, No.4, 1996 1100 MALCOLM W. CHASE

9. References-Annotated 39SCHIJAB P. W. Schenk and H. Jablonowski, "Reactions between atoms at low temperatures," Z. Anorg. Allgem. Chern. 244, Bibliographies 397 (1940); Z. Elektrochem. 45, 650 (1939); preparation. 39SCHlWIE R. Schwarz and H. Wiele, "The bromine oxides. II," J. Prakt. Chern. 152(2), 157-76 (1939); CA 33 4541(5); The following articles are a combination of all references formation. dealing with the bromine oxides. Where possible, we have 40MUN/SPI R. Mungen and J. W. T. Spinks, "The bromine sensitized photodecomposition of ozone," Can. J. Res. 18B, 363-71 tried to include all authors, title, journal, a citation to Chemi­ (1940); CA 35 692(6); formation. cal Abstracts, and an annotation indicating the type of study. 47COLIGAY E. H. Coleman and A. G. Gaydon, "The radicals BrO and In general, dissertations (especially non-US) have not been CBr in flames," Discussions Faraday Soc. (2), 166-9 (1947); CA 43 5312g; spectra, dissociation energy. obtained and read. 47KHAIBOL M. Kharasch, P. B. Bolen, and W. HUrry, "Formation of quinone by the action of bromine oxide on benzene," J. Am. Chern. Soc. 69, 2566 (1947); CA 42 146f; reaction with benzene, toluene, and cyclohexane. 28LEW/SCH B. Lewis and H.-J. Schumacher, "The existence of an ox­ 47PRA A. H. Pratt, "Esterification of cellulose," U.S. 2,429,644 ide of bromine," Z. Phys. Chern., Abt. A 138, 462 (1928); CA 23 3416(7); preparation. (1947); CA 42 P3178h; dehydration of HBr03 to Br205' 29LEW/SCH B. Lewis and H.-J. Schumacher, "Preparation and proper­ catalyst in celluluse:: e::sle::rtflcaliull. ties of a bromine oxide," Z. Anorg. Allgem. Chern. 182, 48FARlKLE L. Farkas and F. S. Klein, "On the photochemistry of some 182-6 (1929); CA 23 5426(3); preparation, decomposition. ions in solution," J. Chem. Phys. 16(9), 886-93 (1948); 29LEW/SCH2 B. Lewis and H.-J. Schumacher, "Thermal reaction CA 50 16345h; enthalpy of formation. between bromine and ozone," Z. Elektrochem. 35, 64~-52 48GAY A. G. Gaydon, Spectroscopy and Combustion Theory, 2nd (1929); CA 24 2033(8); preparation. ed. (Chapman and Hall, London, 1948), p. 92; review, dissociation energy. 30BRA W. C. Bray, "An oxide of iodine, 12°2 , An intermediate compound," J. Am. Chern. Soc. 52, 3580-6 (1930); CA 24 50BREIBRO L. Brewer, L. A. Bromley, P. W. Gilles, and N. L. Lofgren, 5654; in aqueous solution. "Paper 6: The thermodynamic properties of the halides," 30LEW/SCH B. Lewis and H.-J. Schumacher, "A first order solid phase National Nuclear Energy Series 19B, edited by L. L. Quill reaction," Nature 125, 129 (1930); CA 24 2033(8); (McGraw-Hill, New York, 1950); dissociation energy. kinetics. 50RER G. Herzberg, Molecular Spectra and Molecular Structure. 30ZINIRIE E. Zintl and G. Rienacker, "Existence of a volatile bromine /. Spectra of Diatomic Molecules, 2nd ed. (Van Nostrand, oxide," Ber. 63B, 1098-1104 (1930); CA 24 5249(3); Princeton, 1950); spectroscopy. preparation. 51ABE E. Abel, "Halate formation," Monatsh. Chern. 82, 751-4 31LEWIFEI B. Lewis and W. Feitknecht, "The kinetics of gas (1951); CA 46 3890g; intermediate in aqueous solution explosions: the thermal decomposition of ozone sensitized (does not specifically mention Br202)' by bromine vapor," J. Am. Chern. Soc. 53, 2910-34 51PFLISCH A. Pflugmacher, R. Schwarz, and H. J. Rabbin, "Oxides of (1931); decomposition of ozone. bromine. III. The heat of formation of bromine dioxide," Z. 31SPI J. W. T. Spinks, "Photosensitized decomposition of ozone Anorg. Allgem. Chem~264, 204-8 (1951); CA 47 6752i; by bromine," Nature 128, 548 (1931); decomposition of enthalpy of formation. ozone. 52EDW 1. 0. Edwards, "Rate laws and mechanisms of oxyanion 34BRA 0. L. Brady, "Recent advances in science: general and reactions with bases," Chern. Rev. 50, 455--82 (1952); CA organic chemistry," Sci. Prog. 29, 101-9 (1934); CA 28 46 8482f; in aqueous solution, review. 6598(8); review. 53BRE L. Brewer, "The thermodynamic properties of the oxides 34SKR A. Skrabal, "Reactions of alkaline halogen bleaches and their vaporization processes," Chem. Rev. 52, 1-66 [hypohalites]," Z. Elektrochem. Angew. Phys. Chern. 40, (1953); review, dissociation energy. 232-46 (1934); CA 28 4997(1); re-examination of 53GA Y A. G. Gaydon, Dissociation Energies and Spectra of available data in aqueous solution. Diatomic Molecules, 2nd ed. (Chapman and Hall, London, 35BREISCH W. Brenschede and H. J. Schumacher, "Bromine oxide, 1953); dissociation energy. Br20," Z. Phys. Chern. B29, 356-8 (1935); CA 30 37(3); 53KAN N. P. Kanyaev, "Bromination of unsaturated compounds. preparation, decomposition. III. Reaction of addition of hypobromous acid to 36BRE/SCH W. Brenschede and H. J. Schumacher, "The preparation allytrimethyammonium perchlorate," Sbomik Statei and a few properties of bromine oxide of the formula Obshchei Khim. 2, 1172-7 (1953); CA 49 5087f; Br~O," Z. Anorg. Allgem. Chern. 226, 370-84 (1936); CA formation, bromination with HBrO. 30 4419(7); preparation. properties. 53PFL A. Pflugmacher, "Bromine oxides. IV. Trinitrobromo 36RABIWOO E. Rabinowitch and W. C. Wood, "Kinetics of dioxide," Z. Anorg. Allgem. Chem. 273,41-7 (1953); CA

recombination of bromine atoms. II," Trans. Faraday Soc . 48 489f; compound with N02 , questions if the compound .52, YU} -l/ (iY36); LA :;U )~62(l.); dISSOCIatiOn of Br2 in is not Br206 . the presence of O2 . 54ANTIDOS M. Anthar and 1. Dostrovsky, "Ultraviolet absorption 37SCH/SCH R. Schwarz and M. Schmeisser, "A new oxide of bromine spectra of some organic hypohalites," J. Chern. Soc. 1105-

of the formula Br02' I," Ber. 70B, 1163-6 (1937); CA 31 8 (1954); CA 48 6827h; spectrum in CC14 . 6125(6); formation, decomposition. 54COT T. L. Cottrell, The Strengths of Chemical Bonds 37V Al W. M. Vaidya, "Flame spectra of some aliphatic halides. I. (B utterworths, London, 1954), pp. 221-81; estimated bond Methyl iodide." Proc. Indian Acad. Sci. 6A, 122-8 (1937); dissociation energy. CA 32 50(8); spectra. 55PFL A. Pftugmacher, "About bromine trioxide." Angew. Chem. 38SCHI\VIE R. Schwarz and H. Wiele. "The bromine oxide. Br}O," 67, 524 (1955); discussion of reaction scheme. Naturwissenschaften 26. 742 ([938): CA 33 2430(9); 55PFLIRAB A. Pftugmacher, H. J. Rabben, and H. Dahmen, "Bromine preparation. oxides. V. Bromine trioxide," Z. Anorg. Allgem. Chem. 38VAI W. M. Vaidya, "Flame spectra of some aliphatic halides. II. 279, 313-20 (1955); CA 49 14550f; preparation, Ethylbromide," Proc. Indian Acad. Sci. 7a, 321-6 (1938); properties. CA 32 6550(7); spectra.

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56VEN/SUN K. Venkateswarlu and S. Sundaram, "Evaluatio~ of force 62BOY/GRA G. E. Boyd, E. W. Graham, and Q. V. Larsan, "Recoil constants from Raman effect data: molecules, radIcals, and reactions with high intensity slow neutron sources. IV. groups of pyramidal XY3 type," Proc. Phys. Soc. (London) Radiolysis of crystal alkali metal bromates with {'-rays," 1. A 69, 180-3 (1956); CA 50 16345h; vibrational ,Phys.Chem. 66, 300'--7 (1962); CA 57 313h; radiolysis. frequencies. . 62GUEIPAN H. Guenbaut, G. Pannetier, and P. Goudmand, "Excitation 57RAM D. A. Ramsay, "Electronic spectra of polyatomlc free of gases or gas mixtures in a shock tube," Bull. Soc. Chim. radicals." Ann. NY Acad. Sci. 67,485-98 (1957); CA 51 France 1962, 80-6 (1962); CA 57 1753a; formation in 16094a; review of electronic spectra, only passing reference reaction of H S0 and KBr03 induced by shock waves. to BrO (no data). 2 4 62SVE R. A. Svehla, "Estimated viscosities and thermal C;7ST1VCHT R L. Strong, I. C. W. Chien, P. E. Graf, and J. E. Willard, conductivities of gases at high temperatures," NASA Tech. "Studies of iodine atom and bromine atom recombination Rep. R132, 140 pp. (1962); CA 57 79c; thermal following flash photolysis of gaseous 12 and Br2 , " J. Chern. conductivity, viscosity. Phys.26, 1287-95 (1957); CA 51 13580d. 63BURINOR G. Bums and R. G. W. Norrish, "Mechanism of the 58ARV/AYM A. J. Arvia, P. J. Aymonino and H.-J. Schumacher. formation of halogen monoxides during flash photolysis "Formation of solid oxides of bromine in the thermal of halogen + oxygen mixtures," Proc. R. Soc. reaction between bromine and ozone," Anales Asoc. Quim. (London) A 271, 289-95 (I963); CA 58 4076d; flash Arg. 46, 55-65 (1958); CA 52 18048i; refer to CA 53 photolysis. 7849c; formation from Br and 0 • 3 63SCH C. J. Schexnayder Jr., "Tabulated values of bond 58BRE L. Brewer, "Dissociation energies of gaseous oxides," dissociation energies, ionization potentials and electron UCRL 8356, 4 pp. (1958); critical evaluation of affinities for some molecules found in high-temperature dissociation energy. chemical reactions," NASA Tech. Note D-179I. 62 pp. 58DURIRAM R. A. Durie and D. A. Ramsay, "Absorption spectra of the (1963); dissociation energies. halogen monoxides," Can. 1. Phys. 36, 35-53 (1958); CA 63SCHIBRA M. Schmeisser and K. Brandle, "Oxides and oxyfluorides 52 4315b; absorption spectra; rotational and vibrational of the halogens," Adv. Inorg. Chern. Radiochem. 5, 41-89 analysis, dissociation energy. (1963); CA 60 7657b; review. 58MCGINOR W. D. McGrath and R. G. W. Norrish, "The study of 63VENIRAJ K. Venkateswarlu and K. V. Raj::llak~hmL "Tlrf'y-Rrnrlley energy transfer und energy distribution in fast chemical force field and thermodynamic properties: pyramidal XY reaction by flash photolysis and kinetic spectroscopy," Z. 3 type molecules," Indian 1. Pure App!. Phys. 1, 380-2 Phys. Chern. (Frankfurt) 15,245-61 (1958); CA 52 11591f; (1963); CA 60 4823e; vibrations. dissociation energy. 64RAO/SAN C. G. Rama Rao and C. Santhamma, "The mean square 58SIG J. Sigalla. "Reduction of bromates hy halide~ ::lnci th~ amplitudes of vibration in Br03, 10 , and SiBr3 ," Current mechanism of oxidation-reduction reactions," 1. chim. 3 Sci. 33(22), 677-8 (1964); CA 62 6001e; molecular phys. 55, 758-67 (1958); CA 53 7851a; in aqueous solution vibrations. (Br20 2· HP)· 64TREIYAA A. Trei~in and M. Yaacobi, "The electronic spectra of the 58ZEE A. P. Zeelenberg, "Absorption spectrum of the OBr hal ate ions in solution," 1. Phys. Chern. 68, 2487-92 radical," Nature 181,42 (1958); CA 52 10717c; absorption (1964); CA 61 10192e; rejection of Matheson et al. (1960) spectrum. data. 58ARV/AYM A. J. Arvia, P. J. Aymonino, and H. J. Schumacher, 65GLUIMED V. P. Glushko and V. A. Medvedev, "Thermal Constants of "Formation of solid oxides of bromine in the thermal Substances," Volume I (145 pp.), Academy of Sciences, reaction between bromine and ozone," Anales Asoc. Quim. Moscow (1965). Arg. 46. 55-65 (I958); Z. Anorg. Allgem. Chern. 298, 1-8 66BUXIDAI G. V. Buxton, F. S. Dainton, and F. Wilkerson, "The BrO (1959); CA 53 7849c; solid formation from bromine and radical in aqueous solution," Chern. Commun. (l I). 320-1 ozone. (1966); CA 65 8231 a: formation and reaction.~ in prl'<;pnce 58PFL A. PRugmacher, "Formation of solid oxides of bromine in of ultraviolet light. the thermal reaction between bromine and ozone," Z. 66CAM C. CaIY!pbell, "Spectroscopic studies of bromine oxides," Anorg. Allgem. Chern. 298, 9-10 (1959); CA 53 784ge; Ph.D. thesis, Cambridge, England (1966); full citation is not response to Arvia et al. available at this time. 59SCH/JOE M. Schmeisser and K. Joerger. "Reactions with !WonI' 66CARILEV A. Carrington and D. H. Levy, "Electron resonance studies solutions. I. Synthesis of Br02 ," Angew. Chern. 71. 523-4 (1959); CA 54 5315e: preparation from Br,:? and ozone in of free radicals in the gas phase. Detection of ClO, BrO. CFCI, solutions. and NS," J. Chern. Phys. 44(3), 1298-9 (1966); 59SCH H. J. -Schumacher. "Formation of solid oxides of bromine CA 64 15218a; magnetic resonance absorption. ESR of BrO. in the thermal reaction between bromine and ozone," Z. 66CHAIBOY 1. W. Chase and G. E. Boyd. "Radiolysis of the crystal Anorg. Allgem. Chern. 298. 11 (1959): CA 53 7849f: response to Pflugmacher. alkaline earth bromates by cobalt-60 {'-rays," J. Phys. 60BRI/MAT N. K. Bridge and M. S. Matheson, "The flash photolysis of Chern. 70. 1031-6 (1966): proposed formation of BrOc. hal ate and~ other ions in solution:' J. Phys. Chern. 64. 66SPRIPIM R. D. Spratley and G. C. Pimentel. "The [p-IT*J{}' and [s­ 1280-5 (I960): CA 55 7006e: formation in hypobromate IT*]{}' bonds. FNO and 02F2'" 1. Am. Chem. Soc. 88. solutions. 2394-7 (1966); CA 65 3106b; structure, 60GEO 1. W. Geor2:e. "Halides and oxyhalides of the elements of 66VED/GUR V. I. Vedeneyev. L. V. Gurvich, V. N. Kondrafyev, V. A. groups Vb~ and Vlb," Progr. Inorg. Chern. 2, 33-107 Mf'civf'cif'v, and Yeo L. Frankevich, Bond Energies, (1960): CA 57 10507c: review. /oni:.;ation Potentials, and Electronic Affinities (Edward 60MATIDOR M. S. tvlatheson and L. M. Dorfman. "Detection of Arnold. London, 1966). p. 33 (English translation of short-li\'ed transients in radiation chemistry," 1. Chem. Russian 1962 publication)~ dissociation energy, review. 67CAR A. Carrington, "Electron resonance .gaseous free Phvs.32. 1870-1 (960): CA 55 1150c: pulse radi()ly~i, of 61GUE/GOC H. Guenebaut and P. Goudmand. "Molecular radicals," Proc. R. Soc. London, Ser. A 302(1470). 291- 304 (J CA 68 109411 q: ESR. spectroscopY--Dn the excitation in shock wave. of a 967): 67CAR/LEV A. Carrington and D. H. Levy, . 'Electron resonance of free resulting Q.aseous mixture of the action of H2S04 on radicals in the gas phase." Phys. Chem. 71 (j), 2-11. KBr03:- Compt. Rend. 253. 1926-8 (1961): CA 56 1. discussion 11-12 (1967)~ CA 67 69326m: EPR. 15056c: shock wave. formation.

J. Phys. Chern. Ref. Data, Vol. 25, No.4, 1996 1102 MALCOLM W. CHASE

67CARlLEV2 A. Carrington, D. H. Levy, and T. A. Miller, "Stark effect 70BLAIBRO D. A. Blake, R. J. Browne, and G. Bums, "Interaction in gas-phase electron resonance. The dipole moments of potentials involving Br atoms," J. Chern. Phys. 53, 3320-3 CIO, BrO, SH, and III SO," J. Chern. Phys. 47(10), 3801-9 (1970); CA 73 113370w; enthalpy of formation. (1967); CA 68 34133q;EPR, dipole moment. 70BROIBUR J. Brown and G. Bums, "Decomposition of bromine 67CARlLEV3 A. Carrington, D. H. Levy, and T. A. Miller, "Double monoxide studied by kinetic spectroscopy," Can. J. Chern. quantum transitions in gas-phase electron resonance," 48(22), 3487-90 (1970); CA 74 25483a; kinetics and J. Chern. Phys. 47(11), 4859-60 (1967); CA 68 64047q; mechanism of decomposition. EPR. 70CARIDYE A. Carrington, P. N. Dyer, and D. H. Levy, "Gas-phase 67~ARlLEV4 A. Carrington, D. H. Levy, and T. A. Miller, electron resonance spectra of bromosyl iodosyl," J. Chern. "Stark-modulated gas phase electron resonance cavity," Phys. 52(1), 309-14 (1970); CA 72 49474h; ground state Rev. Sci. Instrum. 38(8), 1183-4 (1967); CA 68 64426e; configuration, splitting, rotational constant, EPR. EPR. 70CLY/CRU M. A. A. Clyne and H. W. Cruse, "Rates of elementary 68BUXIDAI G. V. Buxton and F. S. Dainton, "The radiolysis of aqueous reactions involving the BrO (X2II) and 10 (XzII) radicals. solutions of oxybromine compounds: the spectra and 1. Formation and decay of the BrO radical," Trans. Faraday reactions of BrO and Br02 , " Proc. R. Soc. London, Ser. A Soc. 66(9), 2214-26 (1970); CA 73 70238q; kinetics of 304(1479), 427-39 (1968); CA 68 110274d; radiolysis, formation and disproportionation, structure. formation, BrZ02 as an intermediate. 70CLY/CRU2 M. A. A. Clyne and H. W. Cruse, "Rates of elementary 68CAM/JON C. Campbell, J. P. M. Jones, and 1. J. Turner, reactions involving the BrO (X2II) and 10 (X 2II) radicals. "Spectroscopic studies of bromine oxides: the infrared 2. Reactions of the BrO and 10 radicals," Trans. Faraday spectrum of solid bromine monoxide," Chern. Commun. Soc. 66(9), 2227-36 (1970); CA 73 70239r; reaction with (15), 888-9 (1968); CA 69 81958t; force constants, IR nitrogen dioxide. spectrum, structure, also for Br21s0. 70COLICOS M. A. Collins, M. M. Cosgrove, and G. P. Bettertidge, 68EDW/GRE J. O. Edwards, E. F. Greene and J. Ross, "From "Bromine dioxide center in irradiated ZIllC bromate," J. stoichiometry and rate law to mechanism," J. Chern. Educ. Phys. B 3(5), L48-L52 (1970); CA 73 50570p; ESR in 45, 381-5 (1968); CA 69 24473g; proposed structure 'Y-irradiated zinc bromate, 79Br02 and 81Br02' (BrBr02), aqueous solutions, review. 70DAR B. de B. Darwent, "Bond dissociation energies in simple 68GA Y A. G. Gaydon, DissociaTion energies and spectra Of molecules," NSRDS-NDS 31, 1-48 (1970); CA 72 9J85c; diatomic molecules, 3rd ed. (Chapman and Hall, London, review, dissociation energy. 1968), p. 265; review, dissociation energy. 70SERIZAK L. V. Serikov, Yu. A. Zakharov, and A. A. Vasil'ev, 68WAGIEV A D. D. Wagman, W. H. Evans, V. B. Parker, R. H. Schumm, "Radiolysis of alkali metal halates," Tr. Mehvuz. Konf. I. Halow, and S. M. Bailey, "Selected values of chemical Radiats. Fiz. 1967, 321-5 (1970); Ref. Zh., Khim. 1971, thermodynamic properties. Part 1. Tables for the first 23 Abstr. No. 2IB1193; CA 77 95304d; EPR study, formation elements in the standard order of arrangement," of Br03 during radiolysis. NBS-TN7270-3, 31 (1968); enthalpy of formation reported. 70TOMISTU R. E. Tomalesky and J. E. Sturm, "Bromine monoxide 69AMUCZA O. Amichai, G. Czapaki, and A. Treinin, "Flash photolysis from the flash photolysis of bromine-nitrous oxide and of the oxybromine anions," Isr. J. Chern. 7(3), 351-9 bromine-nitrogen dioxide mixtures," J. Chern. Phys. 52(1), (1969); CA 71 I 18332d; formation in photolysis of bromate 472-3 (1970); CA 72 61332t; formation. and bromite. 71BYB J. R. Byberg, "ESR spectra from paramagnetic centers in 69BARIGIL F. Barat, L. Gilles, B. Hickel, and J. Sutton, "Flash irradiated potassium perbromate," J. Chern. Phys. 55(10), photolysis of aqueous solutions of halate ions," 1. Chern. 4867-72 (1971); CA 75 156727b; EPR in potassium Soc. D (24), 1485 (1969); CA 72 61336x; formation in flash perbromate. photolysis of aqueous bromate. 7IBYF/CAR C. R. Byfleet, A. Carrington, and D. K. Russell, "Electric 69BRE/ROS L. Brewer and G. M. Rosenblatt, "Dissociation energies dipole moments of open-shell diatomic molecules," Mol. and free energy functions of gaseous monoxides," Adv. Phys. 20(4), 271-8 (1971); CA 74 147751g; dipole High Temp. Chern. 2, 1-33 (1969); review. moment, EPR. 71CLY/CRU M. A. Clyne an'd H. W. Cruse, "Studies of ground-state 69CAR A. Carrington, "Electron resonance of gaseous diatomic K 2p 312 halogen atoms using atomic resonance absorption," molecules. Magnetic and electric interactions in zil states," Trans. Faraday Soc. 67, 2869-85 (1971); CA 75 145664c; Proc. Colloq. AMPERE (At. Mol. Etud. RadiO Elec. lY6!:l) kinetics, cross-sections. 15, 23-41 (pub. 1969); CA 71 l30594y; EPR. 71KAU/KOL M. Kaufman and C. E. Kolb, "Molecular beam analyzer for 69IP/BUR 1. K. K. lp and G. Bums, "Recombination of Br atoms by identifying transient intermediates in gaseous reactions," flash photolysis over a wide temperature range. II. Br2 in Chern. lnstrum. 3(2). 175-89 (I 97 \): CA 76 76557b: Ht:. Nt:. Ar. Kr. N . ami O ,'' J. ChclII. Phy~. 51, 3414-24 2 2 detection. (I 969): CA 71 129273m; rate constants. 71MlL T. A. Miller, "Alternative explanation for anomalous 69JENIZIE P. W. Jennings and T. D. Ziebarth, "Mechanism of the molecular parameters from electron resonance modified Hunsdiecker reaction," J. Org. Chern. 34(10), 3216-7 (1969); CA 71 123267r; intermediate in experiments," 1. Chern. Phys. 54, 3156-61 (1971); CA 74 Hunsdiecker reaction. 118155k; questions earlier EPR spectra value of X"II 312 69POW/JOH F. X. Powell and D. R. Johnson, "Microwave spectrum of state. K. the BrO free radical," J. Chern. Phys. 50(10),4596 (1969); 710LS J. Olsen, "Radiolysis of frozen solutions containing CA 71 34844j; microwave spectrum, 79BrO and 81BrO data. oxybromine anions," Trans. Faraday Soc. 67(4), 1041-8 (1971); CA 74 132925t; stability in aqueous solution. 70AMIITRE O. Amichai and A. Treinen, "Oxybromine radicals," J. Phys. Chern. 74(20), 3670-4 (1970); CA 73 104276t; 71SHEITUR P. M. A. Sherwood and J. J. Turner, "'The reactions of hydrogen atoms with solids at low temperature. Part I. formation in the photolysis and radiolysis of bromate. Apparatus, hydrocarbon, and hydrogen cyanide reactions," 70BEG/SliB A. Begum. S. Subramanuan, and M. C. R. Symons, J. Chern. Soc. A 1971,2474; no bromine oxides data, only . 'Oxides and oxyions of the nonmetals. Xl. Electron spin a reference to another study. resonance study of the bromate radical in 'Y-irradiated 72ADL T. Adl, "Electron resonance study of gaseous bromine potassium bromate," 1. Chern. Soc. (6), 918-21 (1970); oxide," Ph.D. thesis, Pennsylvania State University, 92 pp. CA 72 138214r: EPR in potassium bromate during (1972); Diss. Abstr. lnt. B 33(12) [Part I], 5710; Order No. radiolysis. 73-13945; CA 79 131120t; EPR.

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72AMONOS T. Amano, A. Yoshinaga, and E. Hirota, "Microwave 74BYB/KIR J. R. Byberg and B. S. Kirkegaard, "ESR spectra of spectrum of the BrO radical. Equilibrium structure and Br03 and BrO~- ," J. Chern. Phys. 60(7), 2594-97 (1974); dipole moment," J. Mol. Spectrosc. 44(33), 594-8 (1972); EPR. CA 78 50058f; moleqIlar constants, 79BrO and 81BrO, 74CAHIRIL R. W. Cahill and J. F. Riley, "Bromine oxide (BrO) microwave spectroscopy. disappearance in the pulse radiolysis of molecular oxygen 72BRI B. J. Brisdon, "Oxides and oxyacids of the halogens," Int. + molecular bromine and nitrogen dioxide + molecular bromine systems," Radiat. Res. 58(1), 25-37 (1974); CA Rev. Sci.: Inorg. Chern. Ser One 3,21551 (1972); CA 76 80 l51056a; formation, disappearance. R120933x: review. 74DHNCLE A. 1. Dhar and F. F. Cleveland, "Bond strengths and other 72BROIBYF 1. M. Brown, C. R. Byfieet, B. 1. Howard, and D. K. constants for diatomic molecules. IV. Calculated values of Russell, "Electron resonance spectra of bromine monoxide, the energies at zero Kelvin. energies equilibrionic, and iodine monoxide, and selenium monofiuoride in J =5/2 constants in the exponential part of the Morse potential rotational levels," Mol. Phys. 23(3), 457-68 (1972); CA 77 energy function, for bonds of the types B-C, B-D, and 107377v; EPR. B-E," Spectrosc. Mol. 23(268), 42":"4 (1974); CA 82 72BUN N. J. Bunce, "Mercury salt pathway for the degradation of 7815w; calculation of force constants, dissociation energies, carboxylic acids to alkyl halides using halogen and and vibrational frequencies. mercuric salts," J. Org. Chern. 37(4), 664-9 (1972); 74DHNCLE2 A. 1. Dhar and F. F. Cleveland, "Bond strengths and other CA 76 98849z; reaction with mercuric oxide and pivalic constants for diatomic molecules. V. Calculated values of acid. the bond strengths, and of the quantities Cr (force-constant 72BUN2 N. Bunce, "Free radical bromination of saturated J. ratio) and Cw (bond-energy ratio), for molecules of several hydrocarbons using bromine and mercuric oxide," Can. J. bond types," Spectrosc. Mol. 23(269), 48-9 (1974); CA 82 Chern. 50(19), 3109-16 (1972); CA 78 28887d; 7814v; calculation offorce constants, dissociation energies, bromination of alkanes. and vibrational frequencies. 72FIE/KOR R. J. Field, E. Koros and R. M. Noyes, "Oscillations in 74LOVITIE F. J. Lovas and E. Tiemann, "Microwave spectral tables. 1. chemical systems. II. Thorough analysis of temporal Diatomic molecules," 1. Phys. Chern. Ref. Data 3(3).609- oscillation in the bromate-cerium-malonic acid system," J. 769 (1974); CA 82 104977h; review, microwave spectral Am. Chern. Soc. 94(25), 8649-64 (1972); CA 78 48508j; data. formation of Br202 in aqueous solution. 74PASIPAV J. L. Pascal, A. C. Pavia, J. Potier, and A. Potier, "New 72RAO C. G. R. Rao, "Centrifugal distortion constants in bromine bromine oxide Br203," C. R. Acad. Sci., Ser. C 279(1), 43-6 (1974); CA 81 98807p; thermal decomposition. trioxide (Br03), iodine trioxide (103), and silicon tribromide (SiBr3) molecules," Sci. Cult. 38(12), 522 74SCH J. Schneider, "Internal partition function of two atom (1972); CA 78 166312p; molecular centrifugal distortion molecules in a polynomial representation," Z. Phys. Chern. constants. (Leipzig) 255(5), 986-96 (1974); CA 82 145259u; 72RAO/SYM K. V. S. Rao and M. C. R. Symons, "Oxides and oxyanions coefficients, partition function. of the nonmetals. XV. Electron spin resonance spectra 74S0LlKEI 1. J. Solomon and J. N. Keith, "Synthesis of halogen of selenium and bromine radicals," J. Chern. Soc .. Dalton compounds in high valence states," AD 775942/6GA, 66 pp. (1974); CA 81 57742v; formation. Trans. (2), 147-50 (1972); CA 76 66023k; EPR. 74TIS R. Tischer, "5. Constants of Radicals. 5.1 Diatomic 72YAN V. M. Yanishevskii, "On certain regularities in the Radicals," Landolt-Bornstein New Ser. Group II 6, 5-90 variation of the fundamental stretching vibration (1974); review, molecular spectra. frequencies of diatomic molecules," Opt. Spcktrosk. 33(4), 75BYBILIN J. R. Byberg and J. Linderberg, "ESR Spectra of chloryl 636-41 (1972); Eng. trans!., Opt. Spectrosc. 33, 349-52 and bromyl (Br02) exchange coupled to molecular (1972); CA 78 64392x; correlation vibrational frequencies oxygen," Chern. Phys. Lett. 33(3), 612-5 (1975); CA 83 and dissociation energies. 105899s; EPR of oxygen exchange coupled complex. 73BYB/SPA J. R. Byberg and J. Spanget-Larsen. "Relation between molecular geometries and nuclear quadrupole coupling 75CLYIWAT M. A. A. Clyne and R. T. Walson, "Kinelics sludks [or constants for some oxy-compounds of bromine and diatomic free radicals using mass spectrometry. 3. chlorine," Chern. Phys. Lett. 23, 247-51 (1973); CA 80 Elementary reactions involving bromine oxide (BrO 125084p; correlation nuclear quadrupole constants and [X2I1]) radicals," 1. Chern. Soc., Faraday Trans. 1 71 (2), geometry. 336 50 (1975); CA 82 160763K; kinetics of reactions. 73DIXIPAR D. A. Dixon, D. D. Parrish, and D. R. Herschbach, 75DALILIN E. Dalgard and J. Linderberg, "Energy weighted overlap in "Molecular beam scattering, general discussion." Faraday magnetic fields. Applications to electron spin resonance Discuss. Chern. Soc. 55, 385-7 (1973); formation. problems," lnt. 1. Quantum Chern., Symp. 9, 269-77 73PANfMIT A. N. Pandey, A. K. Mithal. M. M. Shukla. and G. C. (1975): CA 84 51901m: structure. Singh, "Mean amplitUdes of vibrational and molecular 75GIN/SYM 1. S. Ginns and M. C. R. Symons. "Radiation mechanisms. polarizabilities for some diatomic molecules." Indian 1. r. Inorganic salts in aqueous solutions. Electron spin Pure App!. Phys. 11(1).69-71 (1973); CA 79 47266n; resonance studies of y-irradiated aqueous glasses molecular vibrational amplitudes. containing oxyanions." 1. Chern. Soc., Dalton Trans. (6), 73PARIHER D. D. Parrish and D. R. Herschbach. "Molecular beam 514-21 (1975); CA 83 88617d; formation during chemistry. Persistent collision complex in reaction of radiolysis. EPR. oxygen atoms with bromine molecules," J. Chern. Soc. 75RADfWHl D. St. A. G. Radlein, J. C. Whitehead. and R. Grice, 95(18). 6133-4 ([ 973); CA 79 129458r; formation, ground "Reactive scattering of oxygen atoms. Oxygen + diiodine, state. iodine chloride. dibromine," Mol. Phys. 29(6), 1813-28 73PASIPOT J. L. Pascal and 1. Potier. "Raman spectrum and structure (I975)~ CA 83 103946f; angular distribution. of bromine dioxide." 1. Chern. Soc .. Chern. Commun. (13). 75WOF/MCE S. C. Wofsy, M. B. McElroy and Y. L. Yung, "The 446-7 ( 1973): CA 79 98776m: Raman spectra. structure is chemistry of atmospheric bromine," Geophys. Res. Lett. 2, LiillICIil.:. BI20-l willI i.1 BI-BI uund. 215-1:) (1975); CA 84 110882[, Ul:l;UllClllX uC BIO. 73S0LlDOR D. V. Sokol'skii, Ya. A. Dorfman. and T. L. Rakitskaya. 76CLY/MON M. A. A. Clyne. P. B. Monkhouse. and L. W. Townsend, "Induction period in the reduction of sodium bromate by "'Reactions of oxygen (0 3pJ) atoms with halogens: The phosphine:' Zh. Fiz. Khim. 47. 59-61 (1973); Russ. J. rate constants for the elementary reactions 0 + BrCI, Phys. Chern. 47. 3 J -2 (1973); CA 79 35500\\1: intermediate O+Br" and O+CL." Int. J. Chern. Kinet. 8(3),425-49 in aqueous solutions. (1976)-; CA 85 25845x; reaction with 0, kinetics.

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76MOIIYUR F. B. Moin, Ya. P. Yurkevisc and V. M. Drogovvishkii, 78PAS J. L. Pascal, "Contribution to the studies on halogen "Reaction kinetics of atomic oxygen with chlorine and oxides," Ph.D. Thesis, U.S.T.L. Montpelier, France (1978); bromine," Dokl. Akad. Nauk SSSR 226(4),866-8 (1976). oxidation of bromine by ozone, full citation not available at 76HERISCH C. Herbo, G. Schmitz and M. Van Glabbeke, "Belousov this time. oscillating reaction. I. Kinetics of the bromate-cerium (III) 78ROV/ZHA A. B. Rovinskii and A. M. Zhabotinskii, "Mechanism of reaction," Can. J. Chern. 54, 2628-38 (1976); CA 85 the autocatalytic oxidation of cerium (3 +) by bromate," 16726Ic; Br202 as an intermediate in aqueous solution. Teor. Eksperim. Khim. 14, 183-92 (1978); Theor. Exptl. 760DYINEC K. Ody, A. Nechvatal, and J. M. Tedder, "Liquid-phase Chem. [USSR] 14, 142-50 (1978); CA 89 31486e; Br202 bromination of bromo-butane: variation of the ratio of 1,2- in aqueous solution yields Br02 radicals. to 1,3-dibromobutanes produced," J. Chern. Soc., Perkins 78TEV/SMA D. E. Tevault and R. R. Smardzewski, "Matrix infrared Trans. 2 (5), 521-4 (1976); CA 84 179208h; mechanism of spectrum of the 02Br radica!' Bonding in the 02X species, ., the bromination of halobutanes. J. Am. Chern. Soc. 100(12), 3955-7 (1978); CA 89 76PASIPAV J. L. Pascal, A. C. Pavia, J. Potier, and A. Potier, 119979d; matrix spectrum, IR. "Synthesis and Raman structural analysis of an isomeric 78TEVIWAL D. E. Tevault, N. Walker, R. R. Smardzewski, and W. B. form of dibromine tetroxide (Br20.. (B)). Geometric Fox, "Infrared spectra of the BrO and OBrO free radical structure of this isomer and of bromine trioxide," C. R. and of BrOBr and BrBrO molecules in solid argon at 10 Hebd. Seances Acad. Sci .. Ser. C 280(10), 661-4 (1976); K," 1. Phys. Chern. 82(25), 2728-33 (1978); CA 90 CA 83 18208x; Raman spectra, structure, reactions with 14201m; formation, dimerization, IR spectrum. ULune. 78THIIMOH P. Thirugnanasambandam and S. Mohan, "A new look at 76PAS/PA V2 J. L. Pascal, A. C. Pavia, J. Potier, and A. Potier, molecular vibrations: Part II," Indian J. Phys. 528(3), 173- "Synthesis and Raman spectroscopic study of bromine 8 (1978); CA 90 44141j; molecular vibrations, force hemipentoxide." C. R. Hebd. Seances Acad. Sci., Ser. C constants. 282(1), 53-6 (1976); CA 84 98742a; preparation, 7YADl)fDON M. C. AddIson, J.{. J. Donovan, and J. Garraway, polymeric structure. I 3 "Reactions of 0(2 D2) and 0(2 PJ) with halomethanes," 77CLY/CUR M. A. A. Clyne and A. H. Curran, "Reactions of halogen Faraday Discuss. Chern. Soc. 67, 286-96 (1979); kinetics. atoms, free radicals, and excited states," Gas Kinet. Energy 79CARISAH M. Carlier, K. Sahetchian, and L. R. Sochet, "ESR Tnm'&~r 2, ?'N-Q"i (lQ77): r~vi~w nf kin~tir" evh.lelH.:t: [UI halugell u!l.yraLlical fUlilIatiulI ill the sluLly uf 77CLYIW AT M. A. A. Clyne and R. T. Watson, "Kinetic studies of the heterogeneous decomposition of gaseous hydrogen diatomic free radicals using mass spectrometry. Part 4. The peroxide on halides," Chern. Phys. Lett. 66(3), 557-60 bromine atom + chlorine dioxide radical and bromine (1979); CA 92 11795p; formation. oxide radical + chlorine oxide radical reactions," J. Chern. 79HUB/HER K. P. Huber and G. Herzberg, Molecular spectra and Soc., Faraday Trans. 1 73(8), 1169-87 (1977); CA 87 molecular structure (Van Nostrand, New York, 1979), vol. 173377c; reactions, thermodynamics. 4, pp. 110-1 (1979); CA 90 B195497f; review, EPR 77GILIGAR H. M. Gillespie, J. Garraway, and R. J. Donovan, spectra. I "Reaction of atomic oxygen (2 D2) with halomethanes," J. 79LEU M.-T. Leu, "Rate constant for the reaction bromine oxide Photochem. 7(1), 29-40 (1977); CA 87 60675e; formation. (BrO)+nitric oxide-atomic bromine+nitrogen dioxide," 77GLI C. Glidewell, "Bond energy terms in oxides and Chern. Phys. Lett. 61(2), 275-9 (979); CA 90 157672b; oxo-anions," Inorg. Chim. Acta 24(2),149-57 (1977); CA reaction with NO(g). 87 157428q; bond energy. dissociation energy. 79MICIPA Y 1. V. Michael and W. A. Payne. "Absolute rate constants 77LEE/BEN P. A. Lee and G. Beni. "New method for the calculation of for the reaction of bromine atoms with ozone from 234 to atomic phase shifts: application to extended x-ray 360 K," Int. J. Chem. Kinet. 11, 799-809 (1979); rate absorption fine structure (EXAFS) in molecules and constant for formation of BrO. crystals." Phys. Rev. B 15(6). 2862-83 (1977); CA 86 79MIT Mitsubishi Electric Co., "Bromine recovery from 163150p: bond length. spectroscopy. wastewater containing bromide ion," Jpn. Kokai Tokkyo 77PAS/PAV J. L. Pascal. A. C. Pavia, J. Potier. and A. Potier. Koko.80, 154, 305 (1979); CA 94 177468a; manufacture "Structural studies of bromine oxides by Raman laser from ·wastewater. spectroscopy:' Proc. Int. Conf. Raman Spectrosc. 5th 79NOS/BOD Z. Noszticzius and J. Bodiss, "A heterogeneous chemical (1976).110-1 (pub. 1977): CA 87 210447y: Raman spectra, o:>cillator. The Dclousoy-Zhdbotin~kii-type reaction of structure, thermal decomposition. oxalic acid," J. Am. Chern. Soc. 101, 3177-82 (1979); CA 77SAS/RAO D. L. Sastry and K. V. S. R. Rao, "ESR study of 91 90866t; Br202 as an intermediate in aqueous solution. y-irradiated cadmium bromate dihydrate." Proc. Nuc!. 79WAT/SAN R. T. Watson. S. P. Sander, and Y. L. Yung, "Pressure and Phy" Snlici StMe Phys Symp 20(,. 'iI1f> (1977): CA 90 temperature dependence kinetics ~ttldy of the· nitric oxide 1125981': EPR in y-irradiated cadmium bromate dihydrate. +bromine oxide - nitrogen dioxide + bromine reaction. 77TAD/SHI K, Tado. T. Shioda. and K. Tanaka. "Removal of halogen Implications for stratospheric bromine photochemistry:' J. gas from waste gas." J. Kokai Tokkyo Koho IP 7799966 Phys. Chem. 83(23). 2936-44 (1979); CA 92 47875d; (1977): CA 88 PI09907u; reduction. reaction with NO(g). 77VOGIDRE D. Vogt. \V. Dreves. and 1. Mische. "Energy dependence of 80BAU/COX D. L. Baulch. R. A. Cox. R. F. Hapson Jr., J. A. Kerr, J. differential cross sections in endoergic ion-molecule Troe and R. T. Watson. "Evaluated kinetic and collision processes of negative ions:' Intern. J. Mass photochemical data for atmospheric chemistry." J. Phys. Spectrom. Ion Phys. 24. 285-96 (1977); CA 87 74078z: Chem. Ref. Data 9(2). 2950471 (1980); kinetics. dissociation energy. 80FOEILAM H. D. Foersterling. H. J. Lanberz. and H. Schreiber. 78DL':--

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80JAFIMAI S. Jaffe and W. K. Mainquist, "Bromine decomposition of 81DORIMEH S. Doraiswamy and S. C. Mehrotra, "The collision-induced ozone," J. Phys. Chern. 84, 3277-80 (1980); CA 93 linewidths of chlorine and bromine monoxide perturbed 228487v; dissociation, transition states. by nitrogen," JSR, J. Geophys. Res., Sect. C 86(C6), 80KOL L. Kolditz, "Bromine pxygen compounds," Sitzungsber. 5381-2 ..' (1981); CA 95 51875h; collision-induced Akad. Wiss. DDR Math. Naturwiss. Tech. N14, 11-7 linewidths. (1980); CA 94 166675q; review, formation. 81GROILAU M. Grodzicke, S. Lauer, A. X. Trautwein, and A. Vera, 80LOEIMIL A. Loewenschuss, J. C. Miller, and L. Andrews, "Argon "Application of molecular orbital calculations to matrix absorption spectra of chlorine monoxide, bromine Moessbauer and NMR spectroscopy of halogen-containing monoxide, iodine monoxide, and emission spectra of iodine compounds," Adv. Chern. Ser. 194 (Moessbauer Spectrosc. monoxide," J. Mol. Spectrosc. 80(2), 351-62 (1980); CA Its Chern. Appl.) , 3-37 (1981); CA 96 43242e; dipole 93 16053a; vibrational analysis. from absorption and moment. emission spectra. 81MCK A. R. W. McKellar, "Laser magnetic resonance spectrum 80MOLIMOL 'L. T. Molina and M. J. Molina, "Impact of brominated of bromine oxide (BrO) err lIr2rr 3/2)," J. Mol. Spectrosc. compounds on the stratosphere," EPA-600/9-80-003 [Proc. 86(1), 43-54 (1981); CA 94 112118s; laser magnetic Conf. Methyl Chloroform Other Halocarbon Pollut.] WI resonance spectrum, 79BrO and 81BrO. 1-10/6 (1980); CA 94 144590f; in stratosphere. 81MEN/SAT A. Menon and N. Sathyamurthy, "Negative activation 80NIC M. Nicolet, "The chemical equations of stratospheric and energy for the Cl(Br)O + NO-CI(Br) + N02 reactions," mesospheric ozone," FAA-EE-RO-20 [Proc NATO Aclv J. Phys. (;hem. R~(R), 1021-3 (1981); CA 94 198165q; Study Inst. Atmos. Ozone: Var. Hum. Influences], 823-64 reaction with NO(g). (1980); CA 94 160302u; AD A088889; in atmosphere. 81RAYIWAT G. W. Ray and R. T. Watson, "Kinetics study of the 80SAN S. P. Sander, "Kinetic studies of bromine-monoxide and reactions of nitric oxide with oxygen fluoride, chlorine methylperoxy free radicals by flash photolysis," Ph.D. oxide, bromine oxide, and iodine oxide at 298 K." J. Phys. thesis, California Institute of Technology, 259 pp. (1980); Chern. 85(20), 2955-60 (1981); CA 95 139403p; reaction CA 93 140860a; Diss Abstr. Int. B 40(12, Pt. 1), 5698; with NO(g). Order No. 8012213; full dissertation not available at this 81SANIRAY S. P. Sander, G. W. Ray, and R. T. Watson, "Kinetic study time, reaction kinetics. of the pressure dependence of the BrO + N02 reaction at 80SEDILAZ W. A. Sedlacek, A. L. Lazrus, and B. W. Gandrud, 291S K.," J. Phys. Chern. 85(2), 199-210 (1981); CA 94 "Measurement of stratospheric bromine," FAA-EE-80-00 91082h; reaction with N02(g). [Proc. NATO Adv. Study Inst. Atmos. Ozone: Var. Hum. 81SANIWAT S. P. Sander and R. T. Watson, "Kinetics and mechanism Influences], 273-80 (1980); CA 94 195482e; AD A08889; of disproportionation of BrO radicals," J. Phys. Chern. 85, determination in stratosphere. 4000-7 (1981); CA 95 226406k; formation. 80SUBILOD M. S. Subhano and S. F. Lodhi, "A mechanism for the 81SEG/SUT C. Sehgal, R. G. Sutherland, and R. E. Verralll, photolytic decomposition of hypobromite in aqueous "Sonoluminescence from aqueous solutions of bromine solution at 365 nm, 313 nm, and 253.7 nm," Rev. Roum. and iodine," J. Phys. Chern. 85(4), 315-7 (1981): CA 94 Chim. 25(11-12), 1567-78 ,(1980); CA 95 141909b; 111776t; sono1uminescence. formation. 82ANT S. Antonik, "Kinetic and analytical study of the oxidation 80VELIDUR I. Veltman, A. Durkin, D. J. Smith, and R. Grice, "Reactive of trifluoro- bromo methane between 450 and 550°C," Bull. scattering of hydroxyl radicals: OH + Br2 " Mol. Phys. 40, Soc. Chim. Fr. (3-4, Pt 1), 83-9 (1982); CA 97 109370z; 213-24 (1980); CA 93 156174r; structure in Ar matrix. lack of abstraction reaction. 80YUNIPIN Y. L. Yung, J. P. Pinto, R. T. Watson and S. P. Sander, 82BAU/COX D. L. Baulch, R. A. Cox, P. J. Crutzen, R. E. Hampson, 1. . 'Atmospheric bromine and ozone perturbations' in the A. Kerr, J. Troe and R. T. Watson, "Evaluated kinetic and lower stratosphere," J. Atmos. Sci. 37, 339-53 (1980). photochemical data for atmospheric chemistry. Supplement 81BARICOH M. Barnett, E. A. Cohen, and D. A. Ramsay, "The A 1. CODATA Task Group on Chemical Kinetics," J. Phys. 2 Chern. Ref. Data 11, 327-496 (1982); review of the 2rr j _X rr j absorption spectrum of bromine oxide (BrO)," Can. J. Phys. 59(12), 1908-16 (1981); CA 96 94301f; kinetics of reaction involving BrO, references a BrO electronic absorption spectrum, 81 BrO. enthalilY of formation value. 81BOH/SEN M. C. Bohm, K. D. Sen, and P. C. Schmidt, "Molecular 82COx/SHE R. A. Cox and D. W. Sheppard, "Rate coefficient for the orbital electro- negativity," Chern. Phys. Lett. 78(2), 357- reaction of bromme oxide with hydroperoxy at 303 K," 1. 60 (1981); CA 94 163058e; electronegativity. Chern. Soc., Faraday Trans. 278(8),1383-9 (1982); CA 97 81BROIHOB R.1. Browett, J. H. Hobson, F. E. Davidson and R. Grice, 169579t; reaction with hydroperoxy, kinetics. "Reactive scattering of a supersonic oxygen atom beam 0 82COX/SHE2 R. A. Cox, D. W. Sheppard, and M. P. Stevens, "Absorption Lvdfidcllt~ amI k.inetics of me bromine oxide -r el2 at threshOld," Mol. Phys. 4.i, 113-21 (1':181); CA 95 139050w; BrBrO detected in Ar matrix. (BrO) radical using molecular modulation," 1. Photochem. 8lCLYIMAC M. A. A. Clyne and A. 1. Macrobert, "Kinetic studies of 19(3),189-207 (1982); CA 97 11811Os; formation, frce radical reactions by mass spectroscopy. II. The spectra. R?FFRISMI D. P. Fernie, D. J. Smith, A. Durkin, and R. Grice, reactions of SO I cia. so -r OCIO. aml so -r Bra," Inr. 1. Chern. Kinet. 13(2), 187-97 (1981); CA 94 91106u; "Reactive scattering of a supersonic oxygen atom beam: 0 reaction with SO(g). + Br2'" Mol. Phys. 46, 41-54 (1982); CA 97 98653r; 81 COHIPIC E. A. Cohen, H. M. Pickett, and M. Geller, . 'The rotational ground state. spectrum and molecular parameters of bromine monoxide 82FIE/RAG R.1. Field, N. V. Raghaven, and 1. G. Brummer, "A pulse in the 2rr 3/2 state," 1. Mol. Spectrosc. 87(2), 459-70 radiolysis investigation of the reactions of bromine dioxide (198 Il: CA 95 52007p: microwave spectrum. molecular radical (Br02) with hexacyanoferrate(II), manganese(II), constants. phenoxide ion, and phenol," J. Phys. Chern. 86(13), 2443- 8lDON/ZEL A. F. Donodov, V. V. Zelenov, and V. L. Tal'roze, 9 (1982); CA 97 12499k; reduction. "Mechanism of reactions in the oxygen + ozone + 82FOEILAM H. D. Foersterling, H. 1. Lamberz, H. Schreiber, and W. bromine system." Kinet. Katal. 22(1), 245-7 (I981); CA Zittlau. "Bromine dioxide as an intermediate product of the 94 128159s; formation. decay kinetics. Belousov-Zhabotinskii reaction," Kern. Kozl. 57(3-4), 283-93 (1982); CA 97 155341p; formation.

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82FOEILAM H. D Foersterling, H. L. Lamberz, H. Schreiber, and 84SASIRAO D. L. Sastry and K. V. S. Rama Rao, "Comparative study 31 W. Zittlau, "Bromine dioxide (Br02) as an intermediate in of quadrupole coupling constants of Br03 and BrO- the BelousovcZhabotinskii reaction," Acta Chim. Acad. paramagnetic radical derived from bromate (Br03) ion," Sci. Hung. 110(3), 251-60 (1982); CA 97 188870p; Proc. Nuc!. Phys. Solid State Phys. Symp. 25C, 201-2 formation. (1984); CA 102 141172u; quadrupole coupling constants of . 82MUKlKHI V. N. Mukhin, B. A. Khisamov, and A. G. Kotov, paramagnetic radicals. "Radiation-induced formation of paramagnetic centers in 84SAUITAT J. Sauval and J. B. Tatum, "A set of partition functions and ionic crystals," Khimn. Fiz. (12), 1637-41 (1982); CA 101 equilibrium constants for 300 diatomic molecules of 101095u; formation of paramagnetic center. astrophysical interest," Astrophys. J., Supp!. Ser. 56(2), 82WAGIEVA D. D. Wagman, W. H. Evans, V. B. Parker, R. H. Schumm, 193-209 (1984); CA 101 200866c; equilibrium constant, I. Halow, S. M. Bailey, K. L. Churney, and R. L. Nuttall, partition function. "The NBS tables of chemical thermodynamic properties. 85BENIKRI V. A. Benderskii and A. G. Krivenko, "Time resolutions of . Selected values for inorganic and C1 and C2 organic polarograms of intermediate species," Elektrokhimiya substances in SI units," J. Phys. Chern. Ref. Data 11 Suppl. 21(11), 1507-13 (1985); CA 104 58296h; polarograms. No.2, 2-50 (1982); CA 99 B219862k; enthalpy of 85BJEIBYB N. Bjerre and J. R. Byberg, "Formation of complex defects formation reported, supersedes 65WAGIEV A. involving molecular oxygen by electronhole reactions in 83ALL S. D. Allen, "Spectroscopy and photochemical studies of X-irradiated KCI0 and KBr04, studied by ESR and IR the bromine oxides," Ph.D. thesis, Nottingham, England 4 spectroscopy," J. Chern. Phys. 82(5), 2206-11 (1985); CA (1983); full citation not available at this time. 102 194277p; EPRlIR formation of LX0 , O ]. 83BUS/SIB R. J. Buss, S. J. Sibener and Y. T. Lee, "Reactive scattering 2 2 85BYB 1. R. Byberg, "Oxidation of bromate ion in solid matrices of Oep) + CF I," 1. Phys. Chern. 87(24), 4840 (1983); 3 studied by ESR," J. Chern. Phys. 83(3), 919-24 (1985); ground state assumed by analogy with other halogen oxides. CA 103 147964w; electronic levels within potassium 83BUTIMOR N. I. Butkovskaya. L L Morozov. V. L. Tal' rose. E. S. jJcldllulliU::. Vasiliev, "Kinetic studies of the bromine-oxygen system: 85BYKlGOR I. B. Bykhalo, E. B. Gordon, A. P. Perminov, and V. V. a new paramagnetic particle, bromine dioxide," Chern. Filatov, "EPR study of reactions of excited atoms. The Phys. 79(1), 21-30 (1983); CA 99 146907s; formation, atomic oxygen + molecular bromine bromine monoxide structure. I· atomic bromine ( 2P IIZ' 2P / )' Formation of atomic 83FIEIRAG R. J. Field, N. N. Raghavan, and J. G. Brunimer, "Pulse 3 Z bromine (2pI/ ) in the reaction of hydrogen deuterium and radiolysis study of the reaction between the bromine 2 fluorine with molecular bromine," Khim. Fiz. 4, 770-8 dioxide radical and hexacyanoferrate(4-) ion, (1985); CA 103 60060z; ground and excited states of BrO. manganese(II), phenoxide ion, or phenol,' , Kern. Kozl. 85DUIIHUD M. T. Duignan and J. W. Hudgens, "Multiphoton 59(1-2), 235-50 (1983); CA 101 237999z; formation and ionization spectroscopy of chlorine monoxide (ClO) and reaction in pulse radiolysis of bromite solutions. bromine monoxide (BrO)," J. Chern. Phys. 82(10), 4426- 83FOEILAM H. D. Foersterling, H. J. Lamberz, and H. Schreiber, 33 (1985); CA 103 14011m; ionization spectra. "Formation of bromine dioxide (Br02) in the 85FOEILAM H. D. Foersterling, H. J. Lamberz, and H. Schreiber, Be1ousov-Zhabotinskii reaction of aliphatic alcohols with "Kinetics of the cerium (3+ )lbromine oxide (Br02) bromate," Z. Naturforsch. A 38A(4), 483-6 (1983); CA 99 reaction in sulfuric acid medium," Z. Naturforsch. A: 52982k; formation. Phys., Phys. Chem., K'osmophys. 40A(4), 368-72 (1985); L. A. F. A. 84BAU/COX D. Baulch, R. Cox, R. Hampson Jr., J. Kerr, J. CA 102 210074c; redox reaction with cerium(III) in Troe, and R. T. Watson, "Evaluated kinetic and photochemical data for atmospheric chemistry: Supplement sulfuric acid. II. CODATA task group on gas phase chemical kinetics," 85POYIPIC R. L. Poynter and H. M. Pickett, "Submillimeter, 1. Phys. Chern. Ref. Data 13, 1259-380 (1984); CA 102 millimeter, and microwave spectral line catalog," App!. 152285j; review, kinetics. Opt. 24(14), 2235-40 (1985); CA 103 78568f; 84BOLIBAL J. J. Boland and J. D. Baldeschwieler, "The effect of submillimeter, millimeter, microwave spectral line catalog. thermal vibrations on extended x-ray absorption fine 85STE H. 1. Sternal, "Device for testing blood alcohol content," structure. II," J. Chern. Phys. 81(3), 1145-59 (1984); CA Ger. -:3418373 (1985); CA 104 47016r; pill containing 101 100730k; thermal vibrations effect on EXAFS. Br02 for alcohol determination. 84BURlLAW J K RlInip.tt, N J. T.1lWTp.nce, and I ..L Turner. "Oxygen 86BEN/KRI V. A. Benderskii, A. G. Krivenko, and N V Fedorich, fluorides, non-metal halides, van der Waals molecules, and "Electrode reactions of intermediate species formed during related species: a linking theoretical thread," Inorg. Chern. the reduction of the bromate anion on mercury," 23,2419-28 (1984); CA 101 60416; review. Elektrokhimiya 22(6), 728-34 (1986); CA 105 68947f; 84BUT/KA W J. E. Butler. K. Kawaguchi, and E. Hirota, "Infrared diode reduction on mercury. laser spectroscopy of the bromine oxide (BrO) radical," J. 86BRU/AND W. H. Brune and J. G. Anderson, "In situ observations of Mol. Spectrosc. 104(2), 372-9 (1984); CA 100 l47790z; midlatitude stratospheric chlorine oxide (CIO) and bromine IR spectrum, 79BrO, 81 BrO. oxide (BrO)," Geophys. Res. Lett. 13(13), 1391-4 (1986); 84CLA D. C. Clary, "Rates of chemical reactions dorriinated by CA 106 87998k; in stratosphere. long-range inter-molecular forces," Mol. Phys. 53(1), 3-21 86BRU/STI J. Brunning and L. Stief, "Rl:llt: \.:UIlStlinl fUI thc relictivlI sulfur monoxide + bromine monoxide --> sulfur dioxide (1984); CA 101 198902r; reaction with NO(g). + atomic bromine." 1. Chern. Phys. 85(5), 2591-4 (1986); 84EPIILAR N. D. Epiolis, J. R. Larson, and H. H. Eaton, "Common CA 105 IS9527k; kinetics of reaction with SO(g). denominator by the MOVB method: the structures of water, 86BYB 1. R. Byberg, "ESR study of the complexes chlorine oxide hydrogen peroxide, and their derivatives," Croat. Chern. -molecular oxygen (CIO,Oz) and bromine oxide Acta, 57(S), 1031-S3 (1984); CA 102 172905q; MO-VB -molecular oxygen (BrO,02) formed by decomposition of theory in study of molecular structure. chlorate and bromate anions in solid potassium 84JAC M. E. Jacox, "Ground-state vibrational energy levels of perchlorate," J. Chern. Phys. 84(8), 4235-42 (1986); CA polyatomic transient molecules," 1. Phys. Chem. Ref. Data 104 234l14h; complex with molecular oxygen. 13(4), 94S-1068 (1984); CA 103 4S024x; review of ground 86BYB2 J. R. Byberg, "ESR study of the formation of complex state vibrational levels. defects involving molecular oxygen by electron-hole 84STE Kobe Steel, "Lubricant coatings for petroleum-drilling pipe reactions in x-irradiated potassium chlorate and potassium threads," Japan 841744699 (1984); CA 102 I I 6422t; bromate." J. Chem. Phys. 84(11), 6204-9 (1986); CA 105 lubricant. 32826b; EPR of complex defects.

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86GIN M. L. Ginter, "Spectral studies related to dissociation of 87HILICIC A. J. Hills, R. J. Cicerone, J. G. Calvert, and J. W. Birks, hydrogen bromide, hydrogen chloride, and bromine "Kinetics of the bromine monoxide + chlorine monoxide monoxide," NASA-CR-176698, 92 pp. (1986); CA 105 reactions and implications for stratospheric ozone," Nature 1776S7g; dissociation. , ' (London) 328(6129), 405-8 (1987); CA 107 100125r; full 86HILIMCC G. W. Hills, W. J. McCoy, and R. E. Muenchausen, citation not available at this time, reaction with CIO(g), "Infrared spectroscopy using optogalvanic detection of a kinetics. radio-frequency discharge," AlP Conf. Proc. 146 [Adv. 87LOE/AND L. M. Loewenstein and 1. G. Anderson, "Reactions of Laser Sci.-l], 456-7 (1986); CA 105 143232z; detection radicals with halogen molecules: a frontier orbital technique. interpretation," J. Phys. Chern. 91, 2993-7 (1987); CA 106 86HUI/NET R. E. Huie and P. Neta, "KmetIcs ot one-electron transfer 202539a; proposed cyclic BrBrO sirucLUre. reactions involving chlorine dioxides and nitrogen 87SWAlFLE C. P. Swann and S. J. Fleming, "PIXE spectrometry in dioxide," J. Phys. Chern. 90(6), 1193-8 (1986); CA 104 archaeometry: the development of a system with high . 116829x; I-electron transfer reactions. spatial resolution," Nucl. Instrum. Methods Phys. Res., 86KRE/FAB B. C. Kreuger and P. Fabian, "Model calculations about the Sect. B B22{1-3), 407-10 (1987); CA 106 195454p; reduction of atomospheric ozone by different halogenated determination. hydrocarbons," Ber. Bunsen-Ges. Phys. Chern. 90(11), 88BARIBOT L. A. Barrie, J. W. Bottenheim, R. C. Schnell, P. J. Crutzen, 1062-6 (1986); CA 106 37743c; formation. and R. A. Rasmussen, "Ozone destruction and 86MCE/SAL M. B. McElroy, R.I. Salawitch, and S V. Wofsy, photorh~mical r~ilrtiom; i\t polar ~lInri~e in the lower Arctic "Antarctic ozone: mechanism for the spring decrease," atmosphere," Nature 334(6178), 138-41 (1988); CA 109 Geophys. Res. Lett. 13(12), 1296-9 (1986); CA 106 115299r; in air, ozone destruction in relation to; deals with 36327h; Antarctic stratosphere. BrO (not Br20S)' 86MOZ M. Mozurkewich, "Reactions of hydroperoxo with free 88BARISOL J. W. Barrett, P. M. Solomon, R. L. DeZafra, M. Jaramillo, radicals," J. Phys. Chern. 90(10), 2216-21 (1986); CA 104 L. Emmons, and A. Parrish, "Formation of the Antractic 194019x; reaction with hydroperoxo. ozone hole by the chlorine monoxide dimer mechanism," 86RAZIDOD V. V. Raznikov, A. F. Dodonov, and V. V. Zelenov, Nature (London) 336(6198), 455-8 (1988); CA 110 "Disentangling the fine structure of ionization efficiency 99189t; in lower stratosphere. curves," Int. J. Mass Spectrom. Ion Processes 71(1), 1-27 88BRUITOO W. H. Brune, D. W. Toohey, J. G. Anderson, W. L. Starr, J. (1986); CA 104 142768s; ionization efficiency curves. F. Vedder, and E. F. Danielson, "In situ northern 86SAN S. P. Sander, "Kinetics and mechanism of the 10-10 mid-latitude observations of chlorine monoxide, ozone, and reaction," J. Phys. Chern. 90, 2194-9 (1986); CA 104 bromine monoxide in the wintertime lower stratosphere," 194017v; formation. Sci. 242(4878), 558-62 (1988); CA 110 26966j; in lower 86THO R. C. Thompson, "Reaction mechanisms of the halogens stratosphere. and oxo-ha10gen species in acidic, aqueous solution," Adv. 88COSITEN R. C. Costen, G. M. Tennille, and J. S. Levine, "Cloud Inorg. Bioinorg. Mech. 4, 65-106 (1986); .CA 105 pumping in a one- dimensional photochemical model," 2141/5I/m; review, intermediate in aqueous solutions. 1. Geophys. Res. D: Atmos. 93(D12), 159;1 1-5;1 (1988); 86TUN/KO K. K. Tung, M. K. W. Ko, J. M. Rodriguez, amd N. D. Sze, CA 110 158021g; in troposphere; deals with BrO (not " Are Antartic ozone variations a manifestation of dynamics Br20s)' or chemistry?" Nature (London) 322(6082),811-4 (1986); 88FLE/SWA S. J. Fleming and C. P. Swann, "The Bartol PIXE CA 105 137411r; reaction with CIO(g). microprobe facility: recent applications in archaeology," 86UMAIRAM Y. Umasasidhar, S. Ramaprabhu, and K. V. S. Rama Rao, Nucl. lnstrum. Methods Phys. Res., Sect. B B30(3), 444-53 "Investigation of EFG parameters at the halogen site in (1988); CA 108 166628j; determination in archaeological

X03 and XO~- radicals (X=chlorine, bromine) in certain artifacts. inorganic solids," Z. Naturforsch. A: Phys., Phys. Chem., 88HIL A. J. Hills, "Kinetics investigations of atmospheric Kosmophys. 41A(1-2), 169-70 (1986); CA 105 12341m; chemical reactions," Ph. D. thesis, University of Colorado, thermal vibrations effects on EXAFS. 108 pp. (1987); .Univ. Microfilms lnt., Order No. 87ALLIPOL S. D. Allen, M. Poliakoff, and J. J. Turner, DA8723465; Diss. Abstr. Int. B 48(10), 2951 (1988); CA "Photochemistry of an ozone-bromine complex; the IR 107 100125s; reaction with ClO(g).

spectrum of matrix isolated Br20," J. Mol. Struct. 157, 88HILICIC A. J. Hills, R. J. Cicerone, J. G. Calvert, and J. W. Birks, 1-15 (1987); CA 106 186247w; critique of earlier "Temperature dependence of the rate constant and product vibrational data. channels for the bromine oxide + chlorine oxide reaction," 87BAS/GAV N. G. Basov, V. F. Gavrikov, S. A. Pozdneev and V. A. J. Phys. Chern. 92(7), 1853-8 (1988); CA 108 157109p; Shcheglov, "Possible expansion of the spectral emission kinetics of reaction with CIO(g). range of electronic-transition chemical lasers," Sov. J. 88IGE/STO G. Igel-Mann, H. Stoll, and H. Preuss, "Pseudopotential Quantum Electron. 17(9), 1139-52 (1987). study of monohydrides and monoxides of main group 87ELO/RYN A. Elofson, K. Rynefors, and L. Holmlid, "Monte Carlo elements potassium through bromine," Mol. Phys. 65(6),

~iml1htion of RRKM I1nimoll'rlllilr nl'rompo<;ition in 132C)-36 (l c)&&): CA 111 202162a; calculation of r" ide' molecular beam experiments. V. Product oxygen halide and De. (OX) angular and energy distributions from atomic oxygen 88NET/HUI P. Neta, R. E. Huie, and A. B. Ross, "Rate constants for (3p) + X2 (X = bromine, iodine)," Chern. Phys. reactions of inorganic radicals in aqueous solution," J. 118(1), 1-16 (1987); CA 108 44232e; unimolecular Phys. Chern. Ref. Data 17(3), 1027-284 (1988); CA 109 decomposition. R198144k; reactions, review. 87FLE/SW A S. J. Fleming and C. P. Swann, "Color additives and trace 88SALIWOF R. J. Salawitch, S. C. Wofsy, and M. B. McElroy, elements in ancient glasses: specialized studies using PIXE "Chemistry of OCIO in the Antarctic stratosphere: spectrometry," Nucl. Instrum. Methods Phys. Res., Sect. B implications for bromine," Planet Space Sci. 36(2), 213-24 B22(1-3), 411-8 (1987); CA 106 195455q; determination. (1988); CA 108 226063h; reaction with CI02 ·

J. Phys. Chern. Ref. Data, Vol. 25, No.4, 1996 1108 MALCOLM W. CHASE

88SANIFRI S. P. Sander and R. R. Friedl, "Kinetics and product studies 89FOEINOS H. D. Foersterling and Z. Noszticzius, "An additional of the bromine oxide (BrO) + chlrorine oxide (CIO) negative feedback loop in the classical reaction: implications for Antarctic chemistry," Geophys. Belousov-Zhabotinsklii reaction: malonyl radical as a Res. Lett. 15(8), 887"":90 (1988); CA 109 173873j; reaction second control intermediate," J. Phys. Chern. 93(7), 2740- with CIO(g). 8 (1989); CA 110 142188f; reaction. 88SIN M. Singh, "Thirty-one new diatomic molecules in cosmic 89FRIISAN R. R. Friedl and S. P. Sander, "Kinetics and product studies objects spectra," Astrophys. Space Sci. 140(2), 421-7 of the reaction chlorine monoxide + bromine monoxide (1988); CA 109 82624n; dissociation energy, IP .• using discharge-flow mass spectrometry," J. Phys. Chern. 88TOO/AND D. W. Toohey and J. G. Anderson, "Formation of bromine 93(12), 4756-64 (1989); CA 111 13080m; reaction with chloride eIIuO+) in the reaction of bromine monoxide with CIO(g). chlorine monoxide," J. Phys. Chern. 92(7), 1705-8 (1988); 89KOIR00 M. K. W. Ko, J. M. Rodriquez, N. D. Sze, M. H. Proffitt, CA 108 157132r; kinetics of reaction with CIO(g). W. L. Starr, A. Krueger, E. V. Browell, and M. P. 88TOOIBRU D. W. Toohey, W. H. Brune, and J. C. Anderson, "Rate McCormick, "Implications of AAOE observations of the

constant for the reaction Br + 0 3 -4 BrO + O2 from 248 to seasonal and interannual behavior of Antarctic ozone," J. 418 K: kinetics and mechanism," Intern. J. Chern. Kinet. Geophys. Res. (Atmos) 94(014), 16705-15 (1989); CA 20, 131-44 (1988); CA 108 157114m; reaction, titration 114 68160e; in stratosphere. with NO, enthalpy of formation. 89MELIPOU A. Mellouki, G. Poulet, G. Le Bras, R. Singer, J. P. 88TYK R. J. Tykodi, "Estimated thermochemical properties of Burrows, and G. K. Moortgat, "Discharge flow kinetic some noble-gas monoxides and difluorides." J. Chern. study of the reactions of nitrate radical with bromine, Educ. 65(11), 981-5 (1988); CA 110 220036w; enthalpy of bromine monoxide, hydrogen bromide, and hydrogen atomization. chloride," J. Phys. Chern. 93(24), 8017-21 (1989); CA III 88WAfIIRA V A. Wahner, A. R. Ravishankara, S. P. Sander, and R. R. 241084w; kinetics of reaction with N03 -, EPR. Friedl, "Absorption cross secTion of BrO between 312 and 89SANIFRI S. P. Sander and R. R. Friedl, "Kinetics and product studies 385 nm at 298 and 223 K," Chern. Phys. Lett. 152(6), of the reaction chlorine monoxide + bromine monoxide 507-12 (1988); CA 110 6604lk; UV absorption cross using flash photolysis-ultraviolet absorption," J. Phys. sections. Chern. 93(12), 4764-71 (1989); CA III 15161n; reaction S9ANDIBRU J. G. Anderson, W. H. Brune, S. A. Lloyd, D. W. Toohey, with N02 • S. P. Sander, W. L. Starr, M. Loewenstein, and 1. R. 89S0LlSAN S. Solomon, R. W. Sanders, M. A. Carroll, and A. L. Podolske, "Kinetics of ozone destruction by chlorine Schmeltekopf, "Visible and near-ultraviolet spectroscopy oxide and bromine oxide within the Antarctic vortex: an at McMurdo Station, Antarctica 5. Observations of the analysis based on in situ ER-2 data," J. Geophys. Res., D: diuranal variations of bromine oxide and chlorine dioxide," Atmos. 94(D9), 11480-520 (1989); CA 113 62842m; J. Geophys. Res., D: Atmos. 94(D9), 11393-403 (1989); reactions. CA 113 27063n; in lower stratosphere. 89ATKIBAU R. Atkinson, D. C. Baulch, R. A. Cox, R. F. Hampson Jr., 89STA D. M. Stanbury, "Reduction potentials involving inorganic J. A. Kerr, and J. Troe, "Evaluated kinetics and free radicals in aqueous solutions," Adv. Inorg. Chern. 33, photochemical data for atmospheric chemistry. Supplement 69-138 (1989); CA 111 162816h. III," J. Phys. Chern. Ref. Data 18, 881-1097 (1989); CA 90BIG/BRO P. Biggs, A. C. Brown, C. Canosa-Mas, P. Carpenter, P. S. 111 l21638h; review, reaction enthalpy. Monks, and R. P. Wayne, "The reactions of nitrate radical 89ATKlBAU2 R. Atkinson, D. C. Baulch, R. A. Cox, R. F. Hampson Jr., with atoms and radicals," Phys.-Chem. Behav. Atmos. 1. A. Kerr, and J. Troe, "Towards a quantitative Pollut., (Proc. Eur. Symp. 1989) 5th, 204-9 (pub. 1990); CA understanding of atmospheric ozone," Planet. Space Sci. 115 77627k; reactions with nitrate radical. 37(12), 1605-20 (1989); reactions with ClO. 90BOT/BAR J. W. Bottenheim, L. A. Barrie, E. Atlas, L. E. Heidt, H. 89AUS/JON 1. Austin, R. L. Jones, D. S. McKenna, A. T. Buckland, 1. Niki, R. A. Reinholt, and P. B. Shepson, "Depletion of G. Anderson, D. W. Fahey, C. B. Farmer, L. E. Heidt, M. lower tropospheric ozone during Arctic spring: the Polar H. Proffitt, and others, "Lagrangian photochemical Sunris.~ Experiment 1988," J. Geophys. Res. (Atmos.) modeling studies of the 1987 Antarctic spring vortex. 2. 95(Dl1), 18555-68 (1990): CA 115 12675e; in Seasonal trends in ozone," J. Geophys. Res. (Atmos) troposphere, deals with BrO (not Br308)' 94(DI4), 16717-35 (1989); CA 114 68161f; in 90DAN/CAR F. Danis, F. Caralp, J. Masanet, and R. Lesclaux, "Kinetics stratosphere. of the reaction bromine monoxide + nitrogen dioxide M 89BARIBEC 1. Barnes, K. H. Becker. D. Martin, P. Carlier, G. Mouvier, .....; bromine nitrate + M in the temperature range 263-343 J. L. Jourdain, G. Laverdet, and G. Le Bras, "Impact of K." Chern. Phys. Lett. 167(5), 450-6 (1990); CA 113 halogen oxides on dimethyl sulfide oxidation in the marine 473 16z; reaction with NO} . atmosphere," ACS Symp. Ser. 393 [Biog. Sulfur Environ.]. 90HARIWHI G. L. Harlow, C. A. Whitehurst, H. Robards, D. Deville, 464-75 (1989); CA 112 238441a; reaction. and B. V. Rao, Ash vitrification-a technology ready for 89BOW/BOY G. A. Bowmaker and P. D. W. Boyd, "An SCF-MS-Xa transfer, Proc. Shale Waste Process. Conf. 14th, 143-50 study of the bonding and nuclear quadrupole coupling in (1990), CA 115 986l3t; in vitrified slag. oxygen compounds of the halogens," THEOCHEM 60. 901AC M. E. Jacox, "Vibrational and electronic energy levels of 161-75 (1989); CA 112 84498k; bonding, nuclear polyatomic transient molecules. Supplement," J. Phys. quadrupole coupling. Chern. Ref. Data 19(6), 1387-1546 (1990); CA 115 89BRU/AND W. H. Brune. J. G. Anderson, and K. R. Chan, "In situ 263718r; electronic and vibrational energy levels, review. observations of bromine oxide (BrO) over Antarctica: ER-2 90100 F. Jooste, "Stabilized sterilizing or disinfecting aircraft results from 54° S to 72° S latitude." 1. Geophys. Res. (Atmos.) 94(DI4), 16639-47 (1989); CA 113 halogen-containing composition, method, and apparatus," 236826b: in stratosphere. deals with BrO (not Br308)' PCT lnt. Appl. WO 90 08,558 (j 990); CA 114 P88678h; 89CARISAN M. A. Carroll. R. W. Sanders, S. Solomon. and A. stable disinfectant containing. Schmeltekopf. "Visible and near-ultraviolet spectroscopy 90LEV/OGO W. Levason, J. S. Ogden. M. D. Spicer. and N. A. Young, at McMurdo Sation, Antarctica. 6. Observations of bromine "Characterization of dibromine oxide (Br20) by bromine oxide (BrO)." J. Geophys. Res. (Atmos.) 94(D14), 16633- K-edge EXAFS and IR spectroscopy," 1. Am. Chern. Soc. 8 (1989); CA 113 236825a: in stratosphere, deals with BrO 112(3), 1019-22 (1990); CA 112 68662d; preparation of Br (not BrJOR)' 20. decomposition of Br02 .

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90PHI L. F. Phillips, "Collision-theory calculations of rate 9 10RLIBUR J. J. Orlando, J. B. Burkholder, A. M. R. Bopegedera, and constants for some atmospheric radical reactions over the C. J. Carleton, "Infrared measurements of bromine 2 temperature range 10-600 K," J. Phys. Chern. 94(19), monoxide (X n3/2 )," 1. Mol. Spectrosc. 45(2), 7482-7 (1990); CA 113 135958r; rate constants of 278-89 (1991); CA 114 l10997k; IR spectra, spectral reactions. constants. 90POUILAN G. Poulet, I. T. Lancar, G. Laverdet, and G. Le Bras. "The 91SZAlWOJ E. Szabo-Bardos, L. Wojnarovits, and A. Horvath, "Pulse BrO and CIO reaction and the polar stratospheric ozone," radiolysis studies on hexacyanoferrate(II)-bromate-cyanide in Phys.-Chem. Behav. Atmos. Pollut. [Proc. Eur. Symp., system in ethylene glycol-water solutions," J. Radioana!. 5th, eds. G Restelli and G. Angeletti], 190-5 (1990); CA Nucl. Chem. 147(2), 215-24 (1991); CA 114 174775u; 115 77625h; reactiun wittI CIO(g). formation, reaction/). 90POUILAN2 G. Poulet, I. T. Lancar, G. Laverdet, and G. Le Bras, 91 TUR A. A. Turnipseed. "Kinetics of the reactions of bromine "Kinetics and products of the bromine monoxide monoxide radicals with chlorine monoxide and bromone . + chlorine monoxide reaction," J. Phys. Chern. 94(19), monoxide, and the chemiluminescent reactions of fluorine 218-84 (1990); CA 112 43481f; reaction with CIO(g). with dimethyl sulfide," Ph.D. thesis, University of 90SASIHUI L. V. Sastry, R. E. Huie, and P. Neta, "Formation and Colorado, 151 pp. (1991); Unlv. Microfilms lnt. Order No. reactivity of hypophosphite and phosphite radicals and their DA9117088; Diss Abstr. lnt. B 52(1), 206-7 (1991); CA peroxyl derivatives," J. Phys. Chern. 94(5), 1895-9 (1990); 115 240971j; full citation not available at this time, self CA 112 126245h; electron exchange reaction. reaction, reaction with ClO(g). 90S0L S. Solomon, "Progress towards a quantitative 91TURIBIR A. A. Turnipseed, J. W. Birks, and J. G. Calvert, "Kinetics understanding of Antartic ozone depletion," Nature 347, and temperature dependence of the bromine monoxide 347-54 (1990). + chlorine monoxide reaction," J. Phys. Chern. 95(1 1), 90TUR A. A. Turnipseed, "Kinetics of the reactions of bromine 4356-64 (1991); CA 114 235796a; temperature monoxide radicals with chlorine monoxide and bromine dependence, kinetics. monoxide, and the chemiluminescent reactions of fluorine 92FAN/JAC S.-M. Fan and D. J. Jacob, "Surface ozone depletion in with dimethyl sulfide," PB90-256322, 155 pp. (1990); CA Arctic spring sustained by bromine reactions on aerosols," 114 172367p; self reaction with CIO(g), kinetics, self Nature 359, 522-24 (1992). dlsproportlOnatlOn. 92GILfLEV T. R. Gilson and W. Levason, "Bromine perbromare: 90TURIBIR A. A. Turnipseed, J. W. Birks, and 1. G. Calvert, "Kinetics synthesis and bromine K-edge EXAFS studies," J. Am. of the bromine monoxide radical + bromine monoxide Chern. Soc. 114(13), 5469-70 (1992); CA 117 19295f; radical reaction," J. Phys. Chem. 94(19), 7477-82 (1990); hydrolysis, molecular structure. CA 113 139614y; self disproportionation, Br202 as an 92GILIPOL M. K. Gilles, M. L. Polak, and W. C. Lineberger, intermediate. "Photoelectron spectroscopy of the halogen oxide anions 91ANDrrOO 1. G. Anderson, D. W. Toohey, and W. H. Brune, "Free oxygen fluoride ion (I -), oxygen chloride ion (1-), radicals within the Antarctic vortex: the role of CFC's in oxygen bromide ion (1-), oxygen iodide ion (1-), chlorine Antarctic ozone loss," Sci. 251(4989), 39-46 (1991); CA rlim:irl~ ion (1-), anrl iodine rlimide ion(1 -)," J Chern. 114 128100x; in Antarctic vortex. Phys. 96(11), 8012-20 (1992); CA 117 79197k; electron 91ARS/ZIV M. Arsenovic, M. Zivanovic. and R. Sovljanski, "Weed affinity. control on railways in Yugoslavia," Brighton Crop Prot. 92MCC/HEN J. C. McConnell, G. S. Henderson, L. 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J. Phys. Chern. Ref. Data, Vol. 25, No.4, 1996 1110 MALCOLM W. CHASE

93CURIRAD J. A. Curry and L. F. Radke, "Possible role of ice crystals 94HJEIROS A. Hjelmfelt and 1. Ross, "Electrochemical experiments on in ozone destruction of the lower Arctic atmosphere," thermodynamics at nonequilibrium steady states," 1. Phys. Atmos. Environ. Part 27A(17-18), 2873-8 (1993); CA 120: Chern. 98(39), 9900-2 (1994); CA 121 189795u; reaction. 139704x; kinetics, reaction in troposphere. 94INO A. Inoe, "Electrodeless discharge lamps," Jpn. Kokai 93KUS/SEP R. Kuschel and K. Seppelt, "Bromine bromate, Br203'" Tokkyo Koho JP 06.111,790 [94,111,790], 5 pp. (1994); Angew. Chern. 105(11), 1734-5 (1993); Eng. transl., CA 121 P267357u. Angew. Chern. lnt. Engl. 32(11), 1632-33 (1993); CA 120 94JAC M. E. Jacox, "Vibrational and electronic energy levels of 67967k; crystal data. poly atomic transient molecules," J. Phys. Chern. Ref. Data, 93MAUIW AH R. L. Mauldin III, A. Wahner and A. R. Ravishankara, Monograph No.3, 461 pp. (1994); supersedes 84JAC. 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J. Phys. Chern. Ref. Data, Vol. 25, No.4, 1996 NIST-JANAF THERMOCHEMICAL TABLES FOR THE BROMINE OXIDES 1111

950RLIBUR J. J. Orlando and J. B. Burkholder, "Gas-phase UV/visible 95THOIMON R. P. Thorn Jr., P. S. Monks, L. J. Stief, S.-C. Kuo, Z. absorption spectra of HOBr and Br20," J. Phys. Chern. Zhang and R. B. Klemm, (a) 'A preliminary report on 99(4), 1143-50 (1995); CA 122 60571j; UV/visible the photoionization efficiency spectrum, ionization energy absorption spectra (gas phase). and heat of formation of Br20; and the appearance energy 95THOICRO R. P. Thorn, J. M. Cronkhite, J. M. Nicovich and P. H. of BrO+(Br20),' Brookhaven National Laboratory, Wine, "Laser flash photolysis studies of a radical-radical Report BNL No. 62126, 11 pp. (1995); (b)

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