Calcium Thioarsenites

By the action of concentrated calcium hydrosulphide solution on arsenic trisulphide under varying conditions several different compounds can be obtained. The following formulae have been given for these: CaS.As₂S₃.11H₂O, CaS.4As₂S₃.10H₂O, CaS.9As₂S₃.10H₂O, and 7CaS.As₂S₃.25H₂O.