Portland State University PDXScholar Dissertations and Theses Dissertations and Theses 1976 The chemistry of chromium (VI) and chromium (V) oxide fluorides Patrick Jay Green Portland State University Follow this and additional works at: https://pdxscholar.library.pdx.edu/open_access_etds Part of the Chemistry Commons Let us know how access to this document benefits ou.y Recommended Citation Green, Patrick Jay, "The chemistry of chromium (VI) and chromium (V) oxide fluorides" (1976). Dissertations and Theses. Paper 4039. https://doi.org/10.15760/etd.5923 This Thesis is brought to you for free and open access. It has been accepted for inclusion in Dissertations and Theses by an authorized administrator of PDXScholar. Please contact us if we can make this document more accessible: [email protected]. All ABSTRACT OF THE TllESIS OF Patrick Jay Green for the Master of Science in Chemistry presented April 16, 1976. Title: Chemistry of Chromium(VI) and Chromium(V) Oxide Fluorides. APPROVEO BY MEMBERS OF THE THESIS CO'"o\l TIEE: y . • Ii . ' I : • • • • • New preparative routes to chromyl fluoride were sought. It was found that chlorine ironofluoride reacts with chromium trioxide and chromyl chlo­ ride to produce chromyl fluoride. Attempts were ~ade to define a mechan­ ism for the reaction of ClF and Cr0 in light of by-products observed 3 and previous investigations. Carbonyl fluoride and chromium trioxide react to fom chro·yl fluoride and carbo:i dioxide. A mechanism was also proposed for this react10n. Chromium trioxide 11itl\ l~F6 or WF5 reacts to produce chromyl fluoride and the respective oxide tetrafluoride. 2 Sulfur hexafluoride did not react with Cr03. A limited study of the reaction chemistry of chromyl fluoride was undertaken. The interaction of N02F and NOF and Cr02F2 leads to nitro­ nium and nitrosonium trifluorochromate (VI) salts, respectively. The structure of these compounds was assigned as a cis-dioxo, fluorine bridged polymer on the basis of infrared spectral data and its similarity to previously reported work where the structures were confirmed by x-ray crystallography. The previously reported compound, so2·2Cr0/2• was found to form a 1:2 adduct with acetonitrile which was shown from infra­ red spectral data to contain coordinated CH3CN groups. Chromyl fluoride was found to react with n-hexane to form an Etard complex of non-stoich­ iometric composition. The infrared spectrum of the complex displayed a band which was assigned to a carbonyl group coordinated to a chromium center. Hydrolysis of the complex produced ten different organic com­ pounds, among which hexanoic acid, 2-hexanone, and 3-hexanone were i den­ tified. Tetrachloroethylene, trifluoroethylene, and l,l-difluoroethylene were found to react with chromyl fluoride with only 1, 1-difluoroethylene yielding a stoichiometric complex, CF :cH ·2Cr0 F . The solid products 2 2 2 2 of the reactions of all three olefins with Cr02F2 show an infrared band which was assigned to a carbonyl group coordinated to chromium, like the n-hexane Etard complex. Hydrolysis of CF2:cH2·2Cr02F2 does not yield trifluoroethanol as had been reported .• It was found that Cr03 or Cr0/2 react with excess ClF at 100° to form a red-brown solid which was found to correspond to a composition of CrOF ·0.14ClF to Cr0 F ·o.21ClF. Treatment of this solid with F at 120° 3 2 2 2 3 or reaction of ClF and Cr02F2 at 250° leads to a nonvo l ati l e purple solid which was found to be greatly depleted;,, chlorine. This purple CrOF was assigned to be a fl uori ne-bri dged polymer with termi na 1 3 chromium-o)IYgen double bonds from infrared and Raman spectral informa­ tion. Chromium oxide trifluoride reacts with fluorine at 180° to form CrF and with antimony pentafluoride to produce CrOF '2SbF . 5 3 5 THE CHEMISTRY OF CHROM!Ua(VI) AND CHRO'HUM(V) OXIDE FLUORIDES by PATRICK JAY GREEN A thesis submitted in partial fulfi l lment of the requirements for the de9ree of MASTER or sc1rncE in CHEHISTRY Portland State University 1976 TO THE OFFICE OF GRADUATE STUDIES AND RESEARCH : The melibers of the Cor.mittee approve the thesis of Patrick Jay Green presented Aoril 16, 1976. APPROVED : • y • • • ••p mis try TABLE OF CONTENTS PAGE ACKllOllLEDGEMEtlTS . iii LIST OF FIGURES . • . .. iv LIST OF TABLES v CHAPTER I Experimental. • . • • . l II New Preparations of Chromyl Fluoride 10 I II Some Reaction Chemistry of Chromyl Fluoride 30 IV Preparation and Characterization of Chromium(V) Oxide Trifluoride...... 67 BIBLIOGRAPHY 91 ACKllO:./LEOGEMEilTS The author wishes to thank l!r. Steven Brown for ~o;sistancc in obtaining Raman spectral data and for l!llny productive discussions , Or. Thomas Loehr of the Oregon Graduate Center for use of the Raman spectrometer, Ms . An Mcfarlane for typing the manuscript, Or. Gary Gard for his patience, overall help and advice, and his wife, Susan, for her unvarying support. LIST OF FIGURES FI CURE P/\GE 1 Chr o111Yl Fluoride Etard Reaction Apparatus .... 6 2 Proposed Mechanis~ of the Reaction of Chlorine rlonofluoride and Chr0111iu11 Trioxide at o• .. 23 3 Proposed :1echani sn of the P.eaction of Car!lonyl Fluoride and Chromium Trioxide ............ 24 4 Structure of the F - ion ('' = V, \.I, tlo) • •.• no2 3 45 5 Structures of Metal Oxide Tri ha 1 ides . ..... 82 LIST OF Tf..BLES TJ\llLE PAGF. I P:1ysi ca 1 Proper ti es of Chr0':1yl Fluoride . .. 11 II Previously Reported Preparations of ChrOl'lyl Fluoride . • . 11 III lle11 Preparations of Chror:iyl Fluoride • . 12 IV P.eactions of !·!olybdenw:i and Tungsten Hexa- fl uori des . • . • . • . • . 15 V Proposed Exolanation of the Reaction of Chromium Trioxide and Chlorine r~onofl uoride at o•c ... 26 VI Infrared Absorbances (in cm-1) of Volatile Products of the Reaction of Cro3 and ClF at 0 ·c. ..... 27 VII Bond Lengths and Angles of Chromyl Fluoride...... 31 VIII Chromyl Chloride Oxidation Products . .. 34 IX Infrared Vibrational rrequencies of N02Cr02F3 and NOCr02F J . • . • . • . • . • . 47 X Infrared Vibrational Frequencies of so ·2Cr0zFf 2CH CM and Related 11olc;icules . 2. 51 3 Xl Vibrational Frequencies of the n-Hexane Etard Comp 1ex . 55 XII Infrared Absorbances of n-Hetane Etard Hydro- sylate . • . 58 XIII Vibrational Frequencies of Crromyl Fluoride- Chlorofluoroolefin Reaction Products .•....• 63 XIV Vibration Frequencies of Selected Chlorine Ions and ClF . .. .. .. .. .. 75 XV Observed Vibrational Frequencies of CrOF3·0.21 ClF 76 XVI >:-Ray P01-1der Patterns of CrOF Prepared by T110 ilethods . 3. 78 TABLE PAGE XVI I X-Ray PO'.ider Patterns of Products Obtained from Therr:ial ~~co~posicion o= CrJr3 J~d ~eaction of Cro3 and ClF at 285 . .. .... ........... 80 XVII I f.leta 1-0xygen Stretching Frequencies for Sol id Tr ansition Metal Oxide Trihalides ... .•... 83 XIX Vibr a t ional Frequencies of CrOF , l/CF , and 'ioOF 3 3 3 85 Electr onic Spectr um of the Product of CrOF and xx 3 SbF5 and Other Cr(V) CO'l'l)Ounds . ............ 88 XXI Vi br ational Frequencies of Cr0 Fsb F and 2 2 11 CrF4SbzF11········· · ··· · ··· · ··· · · · · · ········· 90 CHAPTER I EXPERIMENTAL Physical Methods Infrared Spectra. Infrared spectra reported i n this work were re­ corded on Perkin-Elmer Model 467 infrared spectrophotometer over the range 4000 to 250 cm-1 . Spectra of gases were obtained using a Monel gas ce 11 (AgCl windows) with a path length of 8.25 cm . The cell was equipped with a Whitey brass valve and metal 10/30 s joint to adapt to the vacuum system. Solid product spectra were obtained either as nujol mul ls or neat between CsBr or KRS-5 plates. A KBr minipress was also used for solid spectra . Infrared spectra were calibrated using polystyrene film. Raman Spectra. Raman spectra reported in this 1·1ork were recorded on a Jarrel 1 Ash 25-300 Raman spectrometer equipped 1·1ith a Spectra-Physics 250 helium-neon laser for excitation at 5145~ and 5689~. The scattered radiation was detected at approximately 180° geometry with a thermoelectri­ cally cooled S-20 photomultiplier tube and photon counting system. Samples were sea 1ed in 4rllll fused silica tubing . Ultraviolet/Visible spectra. Absorption spectra in the UV/visibl e region reported in this research were obtained using a Cary Model 14 re­ cording spectrophotometer. The technique of S. Brown (61) was used in order to obtain spectra of air-sensitive compounds. Cylindrical fused silica reaction vessels 11ere used for such samples with 1.0 cm path length cells filled 1·1ith water used in the reference beam . X-Ray Powder Spectra. The po1·1der soectra of a 11 new compounds re- ported in the \'/ork were obtained using an XP.D-5 Genera 1 Electric Camera. Samples were contained in 0.5 rrrn Lindemann glass capillaries which 1·1ere loaded in the dry box. flickel-filtered copper Kn radiation was used with an exposure time varying between three and five hours. Magnetic Susceptibility. Values for the magnetic susceptibility of the compounds reported in this work •nere obtained by the Gouy method . Measurements were made using an Alpha AL 7500 water-coo led magnet with 4 in.pole faces and l .5 inch air gap at field strength of 5KG . The 4 nm OD sample tube 11as standardized with Cuso ·5H 0 using mercury( II) 4 2 tetrathiocyanatocobaltate(Il) as the calibrant. Diamagnetic corrections were applied using Pascal's constants. Gas Chromatography. Identification of organic products involved in this 1~ork 1~as facilitated through the use of a Hewlett-Packard Model 57508 gas chromatograph using a flame ionization detector. Solid support used in the six foot by 3/8 inch columns l'las Chromasorb w with a l 0% QF-1 liquid phase .