Cerium Thioarsenates

The addition of sodium orthothio-arsenate to an aqueous solution of a cerous salt produces a pale yellow precipitate of cerous orthothioarsenate. With sodium hydrogen ortho-thioarsenate the precipitate approximates in composition to cerous pyro-thioarsenate. Ceric salts also give pale yellow precipitates, probably eerie orthothioarsenate. Thioarsenates of other rare earth metals have not been described.