Chromium(III) fluoride

Chromium trifluoride

Names
IUPAC name Chromium(III) fluoride
Other names Chromium trifluoride
Identifiers
CAS Number	7788-97-8 Y 16671-27-5 (trihydrate) 123333-98-2 (tetrahydrate)
3D model (JSmol)	Interactive image
ChemSpider	8329529 Y
ECHA InfoCard	100.029.216
PubChem CID	10154021
RTECS number	GB6125000
InChI InChI=1S/Cr.3FH/h;3*1H/q+3;;;/p-3 Y Key: FTBATIJJKIIOTP-UHFFFAOYSA-K Y InChI=1/Cr.3FH/h;3*1H/q+3;;;/p-3 Key: FTBATIJJKIIOTP-DFZHHIFOAR
SMILES [Cr+3].[F-].[F-].[F-]
Properties
Chemical formula	CrF3
Molar mass	108.9913 g/mol (anhydrous) 163.037 g/mol (trihydrate) 181.05 g/mol (tetrahydrate)
Appearance	green crystalline solid
Density	3.8 g/cm3 (anhydrous) 2.2 g/cm3 (trihydrate)
Melting point	1,100 °C (2,010 °F; 1,370 K) (sublimes)
Solubility in water	negligible (anhydrous) sparingly soluble (trihydrate)
Solubility	insoluble in alcohols soluble in HF, HCl
Magnetic susceptibility (χ)	+4370.0·10−6 cm3/mol
Structure
Crystal structure	Rhombohedral, hR24
Space group	R-3c, No. 167
Hazards
Lethal dose or concentration (LD, LC):
LD50 (median dose)	150 mg/kg (guinea pig, oral)
US health exposure limits (NIOSH):
PEL (Permissible)	TWA 1 mg/m3
REL (Recommended)	TWA 0.5 mg/m3
IDLH (Immediate danger)	250 mg/m3
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Y  (what is YN ?)
Infobox references

Chromium(III) fluoride is the name for the inorganic compounds with the chemical formula CrF₃ as well as several related hydrates. The compound CrF₃ is a green crystalline solid that is insoluble in common solvents, but the coloured hydrates [Cr(H₂O)₆]F₃ and [Cr(H₂O)₆]F₃•3H₂O are soluble in water. The trihydrate is green, and the hexahydrate is violet. The anhydrous form sublimes at 1100–1200 °C.

Like almost all compounds of chromium(III), these compounds feature octahedral Cr centres. In the anhydrous form, the six coordination sites are occupied by fluoride ligands that bridge to adjacent Cr centres. In the hydrates, some or all of the fluoride ligands are replaced by water.

Chromium(III) fluoride is produced from the reaction of chromium(III) oxide and hydrofluoric acid:

The anhydrous form is produced from hydrogen fluoride and chromic chloride:

Another method of synthesis of CrF₃ involves thermal decomposition of (NH₃)CrF₆: (NH₄)₃CrF₆ → CrF₃ + 3NH₃ + 3HF A mixed valence Cr₂F₅ is also known.

Chromium(III) fluoride finds some applications as a mordant in textiles and as a corrosion inhibitor. Chromium(III) fluoride catalyzes the fluorination of chlorocarbons by HF.