Chromium(III) chloride

Chromium trichloride

  • Red-violet shining leaflets (anhydrous)
  • Green ( hexahydrate)

Fixed

2.87 g · cm -3

1152 ° C

  • (anhydrous), sparingly soluble in water and ethanol
  • 590 g / l of water (hexahydrate )

Risk

1870 mg · kg -1 ( LD50, rat, oral)

Template: Infobox chemical / molecular formula search available

Chromium ( III) chloride, the chromium salt of an acid with the formula CrCl3. It crystallizes as a hydrate of chromium (III) chloride hexahydrate ( CrCl 3 · 6H 2 O ).

Production and representation

Chromium ( III) chloride can be obtained by the reaction of chromium chloride.

Properties

The hexahydrate [ CrCl2 (H2O ) 4] Cl · 2H2O

It forms crystalline layer structures, the red-violet shine between which van der Waals forces. The salt in pure form is sparingly soluble in water and insoluble in ethanol. Only in the presence of traces of chromium (II ) chloride ( CrCl2 ) (or other reducing agent ) is catalytically possible in water under high heat output a solution process. In solution, differently colored hydratisomere aqua complexes can form, for example, the dark green Dichlorotetraaquachrom (III ) chloride, the bright green Chloropentaaquachrom (III ) chloride or the violet Hexaaquachrom (III ) chloride. This stand between these complexes following equilibria:

Production

Chromium ( III) chloride can be synthesized from metal chromium in a stream of chlorine at 600 ° C. Likewise, the production of chromium ( III) oxide and carbon in a stream of chlorine in excess of 1200 ° C is possible.

Use

As the catalyst for the manufacture of other chromium compounds, chromium plating in electroplating and Waterproof impregnation.

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