Technetium(VI) fluoride

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Technetium(VI) fluoride
Identifiers
CAS number [13842-93-8]
Properties
Molecular formula TcF6
Molar mass 212 g/mol
Appearance yellow crystals
Density 3 g/cm³, solid
Melting point

37.4°C
Boiling point

55.3°C
Structure
Crystal structure cubic
Hazards
EU classification not listed
Except where noted otherwise, data are given for
materials in their standard state
(at 25 °C, 100 kPa)
Infobox disclaimer and references

Technetium(VI) fluoride (TcF6) is a yellow low melting inorganic chemical compound. It was first identified in 1961.[1] 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.[2]

Technetium hexafluoride is prepared by heating the metal in excess of F2 at 400°C[1]

TcF6 is octahedral as shown by the vibrational spectra (IR and Raman) [3] [4] 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.[5]

Preliminary measurements of magnetic moment yield a value of 0.45BM lower than expected for a d1 octahedral compound. [6]

Alkali chlorides + TcF6 in IF5 gives hexafluorotechnetates. [7][8]

TcF6 disproportionates on hydrolysis with aqueous NaOH to form a black precipitate of TcO2.aq [1]

TcF6 in HF + hydrazinium fluoride gives N2H6TcF6 or N2H6(TcF6)2 [9]


[edit] References

  1. ^ a b c The preparation and properties of TcF6 Selig, H.; Chernick, C.L.; Malm, J.G. (1961) J. Inorg. & Nuclear Chem.; 19 ,377
  2. ^ Greenwood, N. N.; Earnshaw, A. (1997). Chemistry of the Elements, 2nd Edition, Oxford:Butterworth-Heinemann. ISBN 0-7506-3365-4. 
  3. ^ 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
  4. ^ 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
  5. ^ 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
  6. ^ 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
  7. ^ New Fluorine Compounds of Technetium A. J. Edwards, D. Hugill & R. D. Peacock Nature (1963),200, 672 ; doi:10.1038/200672a0
  8. ^ Some quinquevalent fluorotechnetates D. Hugill and R. D. Peacock J. Chem. Soc. A, 1966, 1339 - 1341, doi:10.1039/J19660001339
  9. ^ 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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