Cobalt Thiosulphate, CoS₂O₃.6H₂O

Cobalt Thiosulphate, CoS₂O₃.6H₂O, is prepared by mixing equivalent solutions of cobalt sulphate and strontium thiosulphate. After filtering off the insoluble strontium sulphate, the solution is concentrated over sulphuric acid, when a deliquescent, dark red crystalline mass separates out.