Calcium ferricyanide, Ca₃[Fe(CN)₆]₂

Calcium ferricyanide, Ca₃[Fe(CN)₆]₂.(?)12H₂O, may be obtained by oxidising aqueous calcium ferrocyanide with calcium plumbate and carbon dioxide under pressure, at the ordinary temperature. The solid salt is separated by evaporation under reduced pressure. The salt may also be obtained by oxidation of calcium ferrocyanide with chlorine and by neutralising ferricyanic acid with calcium carbonate. It yields needle-shaped crystals, which are stable in dry air.