Chromium pentafluoride
Names
IUPAC name
Chromium(V) fluoride
Other names
Chromium fluoride, Chromium(V) fluoride, Pentafluorochromium, Pentafluoridochromium
Identifiers
3D model (JSmol)
ChemSpider
  • InChI=1S/Cr.5FH/h;5*1H/q+5;;;;;/p-5
    Key: OMKYWARVLGERCK-UHFFFAOYSA-I
  • F[Cr](F)(F)(F)F
Properties[1]
CrF5
Molar mass 146.988 g/mol
Appearance red crystals
Density 2.89 g/cm3
Melting point 34 °C (93 °F; 307 K)
Boiling point 117 °C (243 °F; 390 K)
Structure[2]
orthorhombic
Pbcm, No. 57
a = 782.9 pm, b = 753.4 pm, c = 551.8 pm
4
octahedral
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Chromium pentafluoride is the inorganic compound with the chemical formula CrF5.[3] It is a red volatile solid that melts at 34 °C.[1] It is the highest known chromium fluoride, since the hypothetical chromium hexafluoride has not yet been synthesized.[4]

Chromium pentafluoride is one of the products of the action of fluorine on a mixture of potassium and chromic chlorides.[5]

In terms of its structure, the compound is a one-dimensional coordination polymer. Each Cr(V) center has octahedral molecular geometry.[2] It has the same crystal structure as vanadium pentafluoride.[6]

Chromium pentafluoride is strongly oxidizing, able to fluorinate the noble gas xenon and oxidize dioxygen to dioxygenyl.[2] Due to this property, it decomposes readily in the presence of reducing agents, and easily hydrolyses to chromium(III) and chromium(VI).[7]

Reactions

Chromium pentafluoride can react with Lewis bases such as caesium fluoride and nitryl fluoride to give the respective hexafluorochromate(V) salt.[8]

CrF5 + CsF → CsCrF6

Chromium pentafluoride can also react with the Lewis acid antimony pentafluoride to give the CrF5·2SbF5 adduct. The adduct was found to be a strong oxidizing agent, liquid at room temperature with a melting point of −23 °C.[8]

See also

References

  1. ^ a b Perry, Dale L. (2011). Handbook of Inorganic Compounds, Second Edition. Boca Raton, Florida: CRC Press. p. 125. ISBN 978-1-43981462-8. Retrieved 2014-01-10.
  2. ^ a b c Shorafa, H.; Seppelt, K. (2009). "The structures of CrF5 and CrF5*SbF5". Zeitschrift für anorganische und allgemeine Chemie. 635 (1): 112–114. doi:10.1002/zaac.200800378.
  3. ^ Jacques Guertin; James A. Jacobs; Cynthia P. Avakian, eds. (2004). Chromium(VI) Handbook. CRC Press. p. 30. ISBN 9780203487969.
  4. ^ Riedel, Sebastian; Kaupp, Martin (2009). "The highest oxidation states of the transition metal elements". Coordination Chemistry Reviews. 253 (5–6): 606–624. doi:10.1016/j.ccr.2008.07.014.
  5. ^ A. G. Sharpe (2012). J.H. Simons (ed.). Fluorine Chemistry. Vol. 2. Elsevier. p. 24. ISBN 9780323145435.
  6. ^ A. G. Sharpe (1983). Advances in Inorganic Chemistry. Vol. 27. Academic Press. p. 103. ISBN 9780080578767.
  7. ^ Amit Aora (2005). Text Book Of Inorganic Chemistry. Discovery Publishing House. p. 649.
  8. ^ a b Brown, S. D.; Loehr, T. M.; Gard, G. L. (1976). "The Chemistry of chromium pentafluoride II. Reaction with inorganic systems". Journal of Fluorine Chemistry. 7 (1): 19–32. doi:10.1016/S0022-1139(00)83979-2. ISSN 0022-1139.
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