Sodium ammonio ferrocyanide, Na₃Fe(CN)₅.NH₃

Sodium ammonio ferrocyanide, Na₃Fe(CN)₅.NH₃, is obtained when ammonium hydroxide is allowed to act at 0° C. on a solution of sodium nitroprusside in methyl alcohol.

If the reaction is allowed to proceed at the ordinary temperature, the sodium ammonium salt, Na₂(NH₄)[Fe(CN)₅.NH₃], is obtained. Thus: -

Na₂Fe(CN)₅.NO + 3NH₃ + H₂O = Na₂(NH₄)Fe(CN)₅.NH₃ + NH₄NO₂.