AMMONIUM CYANIDE
Formula : NH4CN; MW 44.056 
Uses
NH4CN 
is used in organic synthesis. Unstable, it is not shipped or sold commercially.
Physical Properties
Colorless crystalline solid; cubic crystal; unstable; density 1.02 g/cm³; decomposes at 36°C; sublimes at 40°C; very soluble in cold water and alcohol; decomposes in hot water.
Preparation
Ammonium cyanide is prepared in solution by bubbling hydrogen cyanide into aqueous ammonia at low temperature:
HCN + NH3(aq) → NH4CN(aq)
It may be prepared in solution by the reaction of calcium cyanide and ammonium carbonate:
Ca(CN)2 + (NH4)2CO3 → 2NH4CN + CaCO3
or barium cyanide and ammonium sulfate:
Ba(CN)2 + (NH4)2SO4 → 2NH4CN + BaSO4
In dry state, NH4CN is made by heating a mixture of potassium cyanide or potassium ferrocyanide with ammonium chloride and condensing the vapors into ammonium cyanide crystals:
KCN + NH4Cl → NH4CN + KCl
Reactions
Ammonium cyanide decomposes to ammonia and hydrogen cyanide; often forming black polymer of HCN:
NH4CN → NH3 + HCN
It undergoes double decomposition reactions in solution with a number of metal salts. It reacts with glyoxal producting glycine (aminoacetic acid)
NH4CN + (CHO)2 → NH2CH2COOH + HCN
Reactions with ketones yield aminonitriles:
NH4CN + CH3COCH3 → NH2CH2CH2CH2CN + H2O
Analysis
Elemental composition: H 9.15%, C 27.23%, N 63.55%. NH4CN may be analyzed by heating the salt and trapping the decomposed products HCN and ammonia in water at low temperatures. The aqueous solution is analyzed for cyanide ion by silver nitrate titrimetric method or an ionselective electrode method; and ammonia is measured by titration or electrode technique (Patnaik, P. 1997. Handbook of Environmental Analysis, Boca Raton, FL: Lewis Publishers).
Toxicity
The solid or its solution is highly toxic. Ingestion can cause death. Exposure to the solid can be harmful as it decomposes to highly toxic hydrogen cyanide and ammonia.
Tags: AMMONIUM CYANIDE, CYANIDE, NH4CN; MW 44.056
