Ammonium cyanide

Ammonium cyanide is an unstable inorganic compound with the formula NH4CN.

Uses
Ammonium cyanide is generally used in organic synthesis. Being unstable, it is not shipped or sold commercially.

Preparation
Ammonium cyanide is prepared by combining solutions of hydrogen cyanide and ammonia:
 * HCN + NH3 → NH4CN

It may be prepared by the reaction of calcium cyanide and ammonium carbonate:
 * Ca(CN)2 + (NH4)2CO3 → 2 NH4CN + CaCO3

In dry state, ammonium cyanide is made by heating a mixture of potassium cyanide or potassium ferrocyanide with ammonium chloride and condensing the vapours into ammonium cyanide crystals:
 * KCN + NH4Cl → NH4CN + KCl

Reactions
Ammonium cyanide decomposes to ammonia and hydrogen cyanide, often forming a black polymer of hydrogen cyanide:
 * NH4CN → NH3 + HCN

It undergoes salt metathesis reaction in solution with a number of metal salts to form metal–cyanide complexes.

Reaction with ketones and aldehydes yield aminonitriles, as in the first step of the Strecker amino acid synthesis:
 * NH4CN + CH3COCH3 → (CH3)2C(NH2)CN + H2O

Toxicity
Ammonium cyanide is highly toxic.