Chromium trifluoride

Chromium fluoride

• 7788-97-8
• 16671-27-5 (trihydrate )
• 123333-98-2 (tetrahydrate )

Volatile, green solid with a pungent odor

Fixed

3.8 g · cm -3

> 1000 ° C.

About 20 mbar (20 ° C)

Soluble in water

Risk

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Chromium (III ) fluoride is a chemical compound of chromium and one of the fluorides. In addition to the anhydrous compound, there are also various hydrates.

Representation

Chromium (III ) fluoride is obtained by the reaction of chromium (III ) oxide and hydrofluoric acid:

The anhydrous form is obtained from hydrogen fluoride and chromium ( III ) chloride:

Properties

Chromium ( III ) fluoride is a green crystalline solid that is insoluble in common solvents, whose colored hydrates [ Cr (H2O ) 6] F3 and [ Cr (H2O ) 3] · 3 H2O F3, however, are water soluble. The trihydrate is green, the hexahydrate is purple. The anhydrous compound sublimes at 1100-1200 ° C. Like almost all the chromium ( III) compounds has chromium ( III ) fluoride octahedral chromium centers. In the anhydrous form, the six coordination sites are occupied by fluorine. The hydrates or all of the ligand is replaced by water. The aqueous solution of a strong acid reaction hydrates, and from 60 ° C starts the crystal dehydration of the hydrates.

Use

Chromium ( III ) fluoride is relatively little use, including as a corrosion inhibitor in anticorrosion paints, for the pickling of wool and cellulose fibers and dyeing with mordant dyes.