Nickel Cobalti-cyanide, Ni₃[Co(CN)₆]₂

Nickel Cobalti-cyanide, Ni₃[Co(CN)₆]₂.12H₂O, may be obtained by precipitating a nickel salt with hydrogen cobalti-cyanide or with the potassium salt. In the latter case the precipitate is not pure, but contains potassium cobalti-cyanide. The salt is bright blue in colour, insoluble in water and acids. With ammonia it yields a blue solution from which crystals of the ammoniate, Ni₃[Co(CN)₆]₂.2NH₃.7H₂O, may be obtained on concentration.