Some Quadrivalent Compounds of Rhenium and Technetium Containing Fluorine
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University of Tennessee, Knoxville TRACE: Tennessee Research and Creative Exchange Masters Theses Graduate School 12-1963 Some Quadrivalent Compounds of Rhenium and Technetium Containing Fluorine David E. LaValle University of Tennessee - Knoxville Follow this and additional works at: https://trace.tennessee.edu/utk_gradthes Part of the Chemistry Commons Recommended Citation LaValle, David E., "Some Quadrivalent Compounds of Rhenium and Technetium Containing Fluorine. " Master's Thesis, University of Tennessee, 1963. https://trace.tennessee.edu/utk_gradthes/3217 This Thesis is brought to you for free and open access by the Graduate School at TRACE: Tennessee Research and Creative Exchange. It has been accepted for inclusion in Masters Theses by an authorized administrator of TRACE: Tennessee Research and Creative Exchange. For more information, please contact [email protected]. To the Graduate Council: I am submitting herewith a thesis written by David E. LaValle entitled "Some Quadrivalent Compounds of Rhenium and Technetium Containing Fluorine." I have examined the final electronic copy of this thesis for form and content and recommend that it be accepted in partial fulfillment of the equirr ements for the degree of Master of Science, with a major in Chemistry. William T. Smith, Jr., Major Professor We have read this thesis and recommend its acceptance: G.E. Boyd, John A. Dean Accepted for the Council: Carolyn R. Hodges Vice Provost and Dean of the Graduate School (Original signatures are on file with official studentecor r ds.) December 11, 1963 To the Graduate Council: I am submitting . herewith a thesis written by-David E. LaValle entitled "Some Quadrivalent Compounds of Rhenium and Technetium Con tain ing Fluorine ." I recommend that it be accepted fo r eighteen quarter·hours credit in partial fulfillment of the requ iremen ts for the deg ree of Mas ter of Science, with a major in Chemis try. Majo r Professo r We have read this thesis and d its acceptance: I Accepted for the Council: Dean of the Graduate School SG1E QUADRIVALENT CG1POUNDS OF RHEN IUM AND TECHNETIUM CONTA IN.ING FLUORINE A Thesis Presented to the Graduate Council of The University of Tennessee In Partial Fulfillme nt of the Requirements for the Degree Master of Science by ·David E. LaValle Decembe r · 1963 ACKNOWLEDGMENT The author wishes to express · his sincere appreciation to Dr. W. T. Sm ith, Jr. for·his guidance and advice prior to , and throughout the co urse of the research; and to Dr. G. E. Boyd for ' his un flagg ing support of the project. To the An a lytical Chem is try Divis ion of Oak Ridge National Laboratory many thanks for the provi- sion of facilities and the great numbe r of analyses pe rf ormed. To othe rs also a de bt is owed: Dr. R. H. Busey for his advice and invaluable a id in the field of spectrophotome try; to Dr. H. Yake l for his efforts toward the solution of some difficult problems in crysta l structure; and especially to R. M. Steele, who se pers istent and un tiring efforts in the interpretation of X-ray dif fraction powder pa tte rns made th is wo rk po ssible. ii TABLE OF·CONTENTS CHAPTER PAGE PART A: ParASSIUM HEXAFLUORORHENATE (IV), ParASSIUM HEXAFLUORO TECHNETATE ( IV) AND RHEN IUM NITROGEN FLUORIDE I . INTRODUCT ION ..•... 1 II. RESULTS AND DISCUSSION .. 4 III. APPARATUS AND PROCEDURES . 11 1. Materials . 11 2. Apparatus . 11 3. Procedures . 13 4. Analyses . 15 IV . SUMMARX AND CONCLUS IONS 16 BIBLIOGRAPHY... 18 PART B: RHENIUM TETRAFLUORIDE I. INTRODUCTION . 21 II. RESULTS AND'DISCUSSION . 23 III. EXPERIMENTAL ...... 27 IV. SUMMARY AND CONCLUSIONS 34 BIBLIOGRAPHY•.. 35 PART ·C: RHENIUM TETRABROMIDE I. INTRODUCTION . 38 II . RESULTS AND DISCUSSION .. 39 iii iv CHAPTER PAGE III. EXPERIMENTAL. 43 A. ReBr4 .. 43 B. K2Rei6. 44 C. Analyses. 45 IV. SUMMARY AND CONCLUSIONS 46 BIBLIOORAPHY. 47 APPENDIX. 49 LIST·OF TABLES TABLE PAGE I. Analyses of Products Volatilized From Previously Presumed Rhenium Tetrabromide (In Per Cent). 41 II. Rhenium and Technetium Compounds: Debye-Scherrer X-Ray ·Diffraction Data (Cu Ka Radiation). so III. Intensities and Interplanar Distances for Some Rhenium Compounds (Cu Ka Radiation) . 51 v LIST OF FIGURES FI GURE PAGE 1. Vacuum Sy stem fo r Transferring Rhenium Hexafluoride to Nickel Tu bes. 2 8 2 . Su blimation Tube. 31 3. Arrangement fo r the Preparation of Rhe nium Tet rafluoride. • 33 vi PART. A POTASSIUM HEXAFLUORORHENATE(IV), POTASSIUM HEXAFLUORO TECHNETATE(IV) AND RHENIUM NITROGEN FLUORIDE CHAPTER I INT RODUCTION ·The compound pot assium· hexaf luororhenat e( IV ) (�2 ReF6) was first _ 1 reported by Ru ff and �wasnik: in .l-934. -At ,this tio;�.e , when.m�ch· of �he early .wo rk _on the chemis.t ry of rhenium was· being done, the·- ot her- anal- ogous·halogen complexes of rhenium.were alreadY.-known • . The preparation of these complexes had generally, been accomplished by the reduction. with iodide ion of rhenium(VII). in.the·form of pot �ssium perrhenate (KRe04), to the qu ad rivalent complex, in a st rong solution of �he app ropr�ate . 2 ,3,4 halogen- ac1.d·. KRe04 +.3KI + 8H C1 � K2ReCl6 + 3/2 I2 +_ 2 KC1 + 4H2 0. 5 I •. and w. Noddack c�lled attention to the dep end ence.of the re- action velocity, on the acid concent ration: in 35 per cent hydrochloric acid it is fairly rapid;· in 8 per cent it is slow. They also stated · that the reduction occurs· in . 50 per ·cent . sulfuric acid, in .glacial * acetic.acid, and in 40 per cent hydrofluoric acid; but they did not desc ribe the product. Ruff and Kw asnik,. however,. ut .ilizing the reaction. in 40 per ·cent hydrof luoric acid, repor�ed· the prep ara�ion of �2 ReF6 as a bright green �compound • * . The st rength of the conc entrated acid as provided abroad seems · ·to t>e · 40 per cent . In the U. S. it is usu ally .-48 per cent. The con- · . stant-.boiling mixture is 35 � 5 per cent. 1 2 No furthe r mention.of the compound appe ared until 1955. Late in 6 that year Pe acock, after noting repe ated failures to duplicate the method. of Ruff and Kwasni� ,. reported the successful preparation. of K2ReF 6 by fusing. the quad rivalent rhenium.complex ammonium iodorhenate (IV) ((NH4 ) 2Re l6) ·in potassium .bifluoride (KHF2) at 250°. It was desc rit?ed as a white compound, remarkably st able,. which-could �e· rec ryst allized from water. 7 Early in 1956, Weise published· the results of his- st udies ·On .. :the alkali fluororhenates and included a:description. of their magnetic prop erties. He ·desc ribed K2ReF6 as a_ white. cOIQpo�nd prepared by passing hydrogen fluoride over K2Re Br6 or K2ReCl6 at 400°· for extended periods of tUne. He also prepared it by the method of Peacock, fusing the more conveniently available K2ReBr6· in KHF2 . The K2ReF6 obtained by this method was pink. He ascribed the pink color to �he replacement of a small fraction.of fluorine ligands by hyd roxyl groups. He found.no difference in the X- ray patterns of the pink and white compounds, . which he attributed to the simil�rity in size of the two ligands. Weise reported that pink � 2ReF6. is· conve rted .to the whit e ·form by repeated .recrystallization& from·40 pe r cent hydrofluo ric acid or by passing hyd rogen fluoride ove r the pink product. · In this latter process :the compound first· became black, then green, and· finally.white. The green. intermediate showed .the X-ray pattern_ for �2ReF6 with a. few ext ra . lines • . The reported chemical analyses for fluorine we re· low: --' 3 pe r c.ent for the pink.co mpound and ,-,J 2 pe r cent for· �he white form. 3 (Peacock's wh it e compound �S· repo rted was � 3 pe r cent low in fluorine.) These discrepancies were not cons idered sign if icant by . Weis e,. however , because of �he uncert ainty ·in. fluorine analyses . The work. in this laboratory· was begun with the aim of produc ing pure K2ReF6 , as a pos sible intermed iate in the preparat ion. of the· lower fluorides-of. rhen ium and as a "stand- in" for the prep.arat ion.of K2TCF6. It· me ant , therefore , the prep aration of the white form of �2ReF6 which both We ise and Peacock-had- described as ·the pure form.of the compound . CHAPI'ER II . RESULTS AND DISCUS S ION Nume rous attempts-we re made to prep�re �2ReF6 following the me thods 1 of Pe acock, 8 Weise, 7 and the earlie r method of Ruff and Kwasnik· . No white salt was ever obtained, although many prepa�ations of pink �2Re F6 we re isolated and identified . The method of Pe acock, fusion of (NH4)2Re i6 in KHF2, was tried with many variations . The products as identified by X-ray dif fraction exami- nation we re predominantly ·KRe04 . When potassium hexaiodorhenat e( IV) In the analogous method of·Weise, fusion of K2Re Br6 in KHF 2, the pink product always resulted . Weise's method of producing_ white K2ReF6 by passing· hy drogen fluoride over 'K2ReBr6 at 450.0 for 10 hours could· not . be duplicated . An.olive-drab product w�s obt ained wh ich . resisted furthe r change even after an additional 6 hou rs of tre atment . ·The· X-ray pattern showed the lines ·characte ristic of K2ReF6 with some add it ional, lines . Many variations of the above methods·we re trie d, - including pro- tection.of the fusions by _ ine rt gas, addition of �y drogen fluoride during fusion, prel imin�ry drying of the �2 by elect rolysis, .