Powdered potassium ferrocyanide (left) and ferricyanide (right), showing their different colours. The colour difference between these related compounds is due to the differing oxidation state of Iron (Latin ferrum). In potassium ferrocyanide, or potassium hexacyanoferrate (II), iron is in the +2 oxidation state. In the ferricycanide or hexacyanoferrate(III), iron is in the +3 oxidation state.
Model release not required. Property release not required.