Chromium pentafluoride

"CrF5" redirects here. For the airport, see Saskatoon/Richter Field Aerodrome.

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

Names
IUPAC name Chromium(V) fluoride
Other names Chromium fluoride, Chromium(V) fluoride, Pentafluorochromium, Pentafluoridochromium
Identifiers
CAS Number	14884-42-5
3D model (JSmol)	Interactive image
ChemSpider	4574207
PubChem CID	5460742
CompTox Dashboard (EPA)	DTXSID601030434
InChI InChI=1S/Cr.5FH/h;5*1H/q+5;;;;;/p-5 Key: OMKYWARVLGERCK-UHFFFAOYSA-I
SMILES F[Cr](F)(F)(F)F
Properties[1]
Chemical formula	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]
Crystal structure	orthorhombic
Space group	Pbcm, No. 57
Lattice constant	a = 782.9 pm, b = 753.4 pm, c = 551.8 pm
Formula units (Z)	4
Coordination geometry	octahedral
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

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

• Chromium difluoride
• Chromium trifluoride
• Chromium tetrafluoride

References

1. 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. 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. 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.