![]() ![]() Reaction with ammonium hydrogen phosphate yields cobalt(II) phosphate:ģCoCl2 + 2(NH4)2HPO4 → Co3(PO4)2 +4NH4Cl + 2HCl Reaction with alkali hydroxide produces cobalt(II) hydroxide: The anhydrous compound also may be obtained by passing chlorine over cobalt powder.Ĭobalt chloride hexahydrate undergoes many double decomposition reactions in aqueous solution to produce precipitates of insoluble cobalt salts.įor example, heating its solution with sodium carbonate yields cobalt(II) carbonate: The solution on concentration and cooling forms crystals of hexahydrate which on heating with SOCl2 dehydrates to anhydrous Cobalt chloride hexahydrate.Īlternatively, the hexahydrate may be converted to anhydrous CoCl2 by dehydration in a stream of hydrogen chloride and dried in vacuum at 100–150☌. Blue leaflets turns pink in moist air hygroscopic the dihydrate is violet blue crystal the hexahydrate is pink monoclinic crystal density 3.36, 2.48 and 1.92 g/cm3 for anhydrous salt, dihydrate and hexahydrate, respectively anhydrous salt melts at 740☌ and vaporizes at 1,049☌ vapor pressure 60 torr at 801☌ the hexahydrate decomposes at 87☌ the anhydrous salt and the hydrates are all soluble in water, ethanol, acetone, and ether the solubility of hydrates in water is greater than the anhydrous salt.Ĭobalt chloride hexahydrate has several applications.Ĭobalt chloride hexahydrate is used in hygrometers as a humidity indicator as a temperature indicator in grinding as a foam stabilizer in beer in invisible ink for painting on glass in electroplating and a catalyst in Grignard reactions, promoting coupling with an organic halide.Ĭobalt chloride hexahydrate also is used to prepare several other cobalt salts and in the manufacture of synthetic vitamin B12.Ĭobalt chloride hexahydrate is prepared by the action of cobalt metal or its oxide, hydroxide, or carbonate with hydrochloric acid:
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