Nickel Monocyanide

Reduction of potassium nickelo-cyanide, K₂Ni(CN)₄, with potassium amalgam yields a red salt, K₂Ni(CN)₃, in which nickel appears to be monovalent. Upon acidifying, an orange-yellow precipitate of the monocyanide is obtained, NiCN. It readily oxidises to nickel cyanide, Ni(CN)₂.