Technetium(VI) fluoride

Chembox new
Name = Technetium(VI) fluoride
ImageFile = Technetium-hexafluoride-2D.png ImageSize = 120
ImageName =
OtherNames =
Section1 = Chembox Identifiers
CASNo = 13842-93-8
Section2 = Chembox Properties
Formula = TcF₆
MolarMass = 212 g/mol
Appearance = yellow crystals
Density = 3 g/cm³, solid
MeltingPt = 37.4°C
BoilingPt = 55.3°C
Section3 = Chembox Structure
CrystalStruct = cubic
Section7 = Chembox Hazards
EUClass = not listed

Technetium(VI) fluoride (TcF₆) is a yellow low melting inorganic chemical compound. It was first identified in 1961. The preparation and properties of TcF₆ Selig, H.; Chernick, C.L.; Malm, J.G. (1961) J. Inorg. & Nuclear Chem.; 19 ,377] In this compound technetium has an oxidation state of +6, and with TcCl₆ has the highest oxidation state found in technetium halides. In this respect technetium differs from rhenium which forms the heptafluoride, ReF₇. [Greenwood&Earnshaw]

Technetium hexafluoride is prepared by heating the metal in excess of F₂ at 400°C

TcF₆ is octahedral as shown by the vibrational spectra (IR and Raman) Vibrational Spectra of MoF₆ and TcF₆ Howard H. Claassen, Henry Selig, and John G. Malm J. Chem. Phys. 36,11, 2888 (1962); doi|10.1063/1.1732396 ] [ Raman Spectra of MoF₆, TcF₆, ReF₆, UF₆, SF₆, SeF₆, and TeF₆ in the Vapor State Howard H. Claassen, Gordon L. Goodman, John H. Holloway, and Henry Selig J. Chem. Phys. 53, 1, 341 (1970); doi|10.1063/1.1673786] The low temperature orthorhombic form converts to the higher symmetry bcc (body centred cubic) form at room temperature, in a similar way to other hexafluorides e.g. RhF₆, OsF₆. [X-Ray Diffraction Studies of Some Transition Metal Hexafluorides Siegel S and Northrop D A Inorg chem 5, 12, 2187 - 2188; doi|10.1021/ic50046a025]

Preliminary measurements of magnetic moment yield a value of 0.45BM lower than expected for a d¹ octahedral compound. [ Magnetic Susceptibility of ReF₆ Selig, H; Cafasso, F A.; Gruen, D M.; Malm, J G. Journal of Chemical Physics, 36, 3440-3444 doi|:10.1063/1.1732477]

Alkali chlorides + TcF₆ in IF₅ gives hexafluorotechnetates. [ New Fluorine Compounds of Technetium A. J. Edwards, D. Hugill & R. D. Peacock Nature (1963),200, 672 ; doi|10.1038/200672a0] [ Some quinquevalent fluorotechnetates D. Hugill and R. D. Peacock J. Chem. Soc. A, 1966, 1339 - 1341, doi|10.1039/J19660001339 ]

TcF₆ disproportionates on hydrolysis with aqueous NaOH to form a black precipitate of TcO2.aq

TcF₆ in HF + hydrazinium fluoride gives N₂H₆TcF₆ or N₂H₆(TcF₆)₂ [ Hydrazinium(+2) hexafluorometalates(IV) and -(V) in the 4d and 5d transition series Frlec B, Selig H, and Hyman H.H Inorg Chem Vol. 6, 10: (1967) 1775 - 1783; doi|10.1021/ic50056a004]

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