Ferrous Cobalti-cyanide, Fe₃[Co(CN)₆]₂

Ferrous Cobalti-cyanide, Fe₃[Co(CN)₆]₂, is precipitated as a slightly yellow amorphous mass on mixing solutions of ferrous sulphate and potassium cobalti-cyanide. The corresponding ferric salt has also been prepared. If precipitated from hot solutions it is yellow in colour, but in the cold a greenish precipitate is obtained after standing for a few minutes. This precipitate becomes yellow on boiling.