Cobalt ferrocyanide, Co₂Fe(CN)₆

Cobalt ferrocyanide, Co₂Fe(CN)₆.7H₂O, is obtained by neutralising the free acid with cobalt hydroxide. It is less stable than the corresponding nickel salt. It is green in colour; oxidised by chlorine water to ferricyanide and by bromine water to hydrated cobaltic oxide.

On boiling with concentrated hydrochloric acid, the acid salt CoH₂Fe(CN)₆.4H₂O, is obtained.

The tri-ammoniate, Co₂Fe(CN)₆.3NH₃, has been prepared.