ammoniumnitriitin

Ammonium nitrite (NH4NO2) is an inorganic compound composed of the ammonium cation (NH4+) and the nitrite anion (NO2−). It is the ammonium salt of nitrous acid. In Finnish sources the compound is called ammoniumnitriitti, with the genitive form ammoniumnitriitin.

The compound is typically encountered as a white crystalline solid that is inherently unstable and tends to decompose rather than persist at ambient conditions. The principal decomposition reaction is NH4NO2 → N2 + 2 H2O, which releases energy in the process. Because decomposition can be rapid, ammonium nitrite is of concern from a safety perspective.

Formation and occurrence are often discussed in terms of it being an intermediate rather than a stable bulk material. It can form in situ by the reaction of ammonia with nitrous acid, or by other ammonium–nitrite equilibria, but it is short-lived under ordinary laboratory or storage conditions due to its tendency to decompose.

Safety and handling are important considerations. Ammonium nitrite is a hazardous material that can decompose explosively under heat, shock, or friction and may act as an oxidizer. It should be stored and handled only under appropriate laboratory conditions, with precautions to avoid heat, friction, acids, or incompatible reducing agents.

See also ammonium nitrate; nitrite; nitrous acid.