A Study of the Double Chlorids of Potassium and Arsenic

Abstract

As the antimony in the black salt of Setterberg has the valence of four, it appears to be a member of the series of hexahalids . . . The primary object of this work was to prepare, if possible, the corresponding salt of potassium amd arsenic. Previous work along the same line has been done in the Washington and Lee labratory, except that the efforts have been to precipitate the salts from cold solutions while in this case the solutions were all hot. All these earlier attempts have been for the most part, unsuccessful, altho in one instance on record a very dark brown salt having the octahedra form was prepared. But as these crystals were very closely associated with some extremely minute other crystals as arsenious oxid and probably an arsenate, their composition could not be definately established. The work was done with rubidum chlorid so there is a possibility that their formula was Rb2AsCl6, a member of the same series . All efforts in connection with this paper were in the main, unsuccessful, but several very interesting facts were brought out regarding the equilibrium of arsenic acid and potassium chlorid in a hot solution of hydrochloric acid. [From introductory section]