Vanadium pentafluoride

From Wikipedia, the free encyclopedia
Jump to: navigation, search
Vanadium(V) fluoride
Kristallstruktur Vanadium(V)-fluorid.png
Identifiers
CAS number 7783-72-4
PubChem 165641
Properties
Molecular formula VF5
Molar mass 145.934
Appearance colorless solid
Density 2.502 g/cm3 (solid)
Melting point 19.5 °C
Boiling point 48.3 °C
Related compounds
Other cations Niobium(V) fluoride
Tantalum(V) fluoride
Related Vanadium compounds Vanadium(V) oxide
Vanadium trifluoride
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
 YesY (verify) (what is: YesY/N?)
Infobox references

Vanadium(V) fluoride is an inorganic compound with the chemical formula VF5, and is the only known pentahalide of vanadium. In the solid, it form is a infinite polymer.[1] At room temperature, it is a colorless volatile liquid, consisting of the pentacoordinate monomer.[citation needed]

Synthesis[edit]

It can be prepared by fluorination of vanadium metal:[2][3]

2 V + 5 F2 → 2 VF5

Alternatively, disproportionation of vanadium tetrafluoride yields equal amounts of the solid trifluoride and the volatile pentafluoride:[4][5][6]

2 VF4 → VF3 + VF5

This conversion is conducted at 650 °C.

Characteristics[edit]

Like other electrophilic metal halides, it hydrolyzes, first to the oxyhalide:

VF5 + H2O → VOF3 + 2 HF

Then to the binary oxide:

2 VOF3 + 3 H2O → V2O5 + 6 HF

Hydrolysis is accelerated in the presence of base. Despite its tendency to hydrolyze, it can be dissolved in alcohols.

It is a Lewis acid:[7][8][9]

VF5 + KF → KVF6

References[edit]

  1. ^ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. p. 989. ISBN 0080379419. 
  2. ^ Trevorrow, L. E.; Fischer, J.; Steunenberg, R. K. (1957). "The Preparation and Properties of Vanadium Pentafluoride". Journal of the American Chemical Society 79 (19): 5167–5168. doi:10.1021/ja01576a023. 
  3. ^ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. p. 989. ISBN 0080379419. 
  4. ^ Ruff, Otto; Lickfett, Herbert (1911). "Vanadinfluoride". Berichte der deutschen chemischen Gesellschaft 44 (3): 2539–2549. doi:10.1002/cber.19110440379. 
  5. ^ Cavell, R. G.; Clark, H. C. (1963). "Thermochemistry of vanadium fluorides". Transactions of the Faraday Society 59: 2706. doi:10.1039/TF9635902706. 
  6. ^ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. p. 989. ISBN 0080379419. 
  7. ^ Справочник химика / Редкол.: Никольский Б.П. и др.. — 3-е изд., испр. — Л.: Химия, 1971. — Т. 2. — 1168 с. (Russian)
  8. ^ Химическая энциклопедия / Редкол.: Кнунянц И.Л. и др.. — М.: Советская энциклопедия, 1995. — Т. 4. — 639 с. — ISBN 5-82270-092-4 (Russian)
  9. ^ Лидин Р.А. и др. Химические свойства неорганических веществ: Учеб. пособие для вузов. — 3-е изд., испр. — М.: Химия, 2000. — 480 с. — ISBN 5-7245-1163-0 (Russian)

Other reading[edit]

  • Arnold F. Holleman, Nils Wiberg: Lehrbuch der Anorganischen Chemie, 102. Auflage, de Gruyter, Berlin 2007, S. 1545, ISBN 978-3-11-017770-1.