Silver Tungstocyanide, Ag₄[W(CN)₈]

Silver Tungstocyanide, Ag₄[W(CN)₈], is obtained as a yellow amorphous powder by adding a silver salt to a solution of the potassium tungstocyanide. It is quite insoluble in water and acids, but readily reacts with metallic chlorides with double decomposition. It is decomposed by sunlight. It dissolves in concentrated ammonia solution, forming the ammine salt, [AgNH₃]₄[W(CN)₈], which separates, on cooling, as bright yellow crystals. This compound is stable in an atmosphere of ammonia and in the dark, but in air it loses ammonia and in sunlight turns yellowish red.