Cobalt Chlorate, Co(CoO₃)₂

Cobalt Chlorate, Co(CoO₃)₂, may be obtained by double decomposition of solutions of cobalt sulphate and barium chlorate. The solution, when Concentrated by exposure to sulphuric acid at temperatures below 18° C., yields unstable dull red rhombic crystals of the hexahydrate, Co(CoO₃)₂.6H₂O. These melt at about 18.5° C. with separation of the tetrahydrate, Co(CoO₃)₂.4H₂O, which is fairly stable at low temperatures, but becomes less so as the temperature rises up to about 61° C., at which point dehydration takes place. Even below this temperature a certain amount of decomposition takes place, with evolution of chlorine and oxygen, an oxide of cobalt being simultaneously produced. A bright red dihydrate, Co(CoO₃)₂.2H₂O, may be obtained by prolonged exposure of the tetrahydrate to the action of phosphorus pentoxide.

The solubility of cobalt chlorate in water is as follows:

Temperature ° C	0	10.5	18	21	35	47	61
Grams of Co(CoO3)2 per 100 grams solution	57.45	61.83	64.19	64.39	67.09	69.66	76.12
Solid phase	Co(CoO3)2.6H2O		Co(CoO3)2.4H2O