Chromium(II) fluoride

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Chromium(II) fluoride

     Cr2+      F−
Other names

chromium difluoride, chromium fluouride, chromous fluoride

Identifiers
CAS number 10049-10-2
PubChem 66229
ChemSpider 59614
EC number 233-168-0
Jmol-3D images {{#if:[F-].[F-].[Cr+2]|Image 1
Properties
Molecular formula CrF2
Molar mass 89.99 g mol−1
Appearance blue-green iridescent crystals[1]
hygroscopic, turns to Cr2O3 when heated in air[1]
Density 3.79 g/cm3[1]
Melting point 894°C[1]
Boiling point >1300°C[1]
Solubility in water 76.7 g/100 mL
Structure
Crystal structure monoclinic[1]
Thermochemistry
Std enthalpy of
formation ΔfHo298		 -8.645 kJ/g (solid)
Hazards
EU classification Xn C
R-phrases R20/21/22, R31, R34
S-phrases S25, S26, S27/28, S36/37/39, S45
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
Infobox references

Chromium(II) fluoride is an inorganic compound with the formula CrF2. It exists as a blue-green iridescent solid. Chromium(II) fluoride is sparingly soluble in water, almost insoluble in alcohol, and is soluble in boiling hydrochloric acid, but is not attacked by hot distilled sulfuric acid or nitric acid. Like other chromous compounds, chromium(II) fluoride is oxidized to chromium(III) oxide in air.[2]

Preparation and structure

The compound is prepared from chromium(II) chloride and hydrogen fluoride:

CrCl2 + 2 HF → CrF2 + 2 HCl

Like many difluorides, CrF2 adopts a structure like rutile with octahedral molecular geometry about Cr(II) and trigonal geometry at F-. Two of the six Cr-F bonds are long at 2.43 Å, and four are short near 2.00 Å.[3]

See also

External links

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 Perry, Dale L. (2011). Handbook of Inorganic Compounds, Second Edition. Boca Raton, Florida: CRC Press. p. 120. ISBN 978-1-43981462-8. Retrieved 10-01-2014. 
  2. ↑ Merck Index, 14 ed. entry 2245
  3. ↑ Jack, K. H.; Maitland, R. "Crystal structures and interatomic bonding of chromous and chromic fluorides" Proceedings of the Chemical Society, London (1957), 232. doi:10.1039/PS9570000217
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