Zinc potassium ferrocyanide, Zn₃K₂[Fe(CN)₆]₂

Zinc potassium ferrocyanide, Zn₃K₂[Fe(CN)₆]₂, is obtained as an insoluble precipitate on adding an excess of potassium ferrocyanide to a zinc salt in aqueous solution.

By adding sulphuric acid to a portion of the clear solution and estimating the excess of potassium ferrocyanide by titration with permanganate, the method may be made a convenient one for the estimation of zinc.