Platinum Arsenites

Platinic Orthoarsenite, Pt₃(NaO₃)₄, was described by Stavenhagen as a pale yellow precipitate formed on the addition of alcohol to a mixture of an aqueous solution of arsenious oxide and an alcoholic solution of platinic chloride. The precipitate is unstable, decomposing at ordinary temperatures into arsenic pentoxide and arsenical platinum. Platinic pyroarsenite, PtAs₂O₅, is obtained in a manner similar to that employed for the corresponding palladium salt described above. It is not attacked by caustic alkali, but decomposes when heated. A complex ammonium platinous arsenite of composition 5(NH₄)₂O.As₂O₃.3(2PtO.As₂O₃).7H₂O has been described.