The Online Encyclopedia and Dictionary






Ammonium nitrate



Name Ammonium nitrate
Appearance White solid

Physical Attributes

Formula weight 80.0 amu
Melting point 442 K (169 °C)
Boiling point decomposes at 483 K (210 °C)
Density 1.7 ×103 kg/m3
Crystal structure ?
Solubility 208 g in 100g water


May cause irritation.
Eyes May cause irritation.
More info Hazardous Chemical Database

Except where noted, all data was produced under conditions of standard temperature and pressure.

The chemical compound ammonium nitrate, the nitrate of ammonia with chemical formula NH4NO3, is commonly used in agriculture as a high-nitrogen fertilizer. As a strong oxidizing agent, it has applications as a component of explosives. In the latter use, it is mixed with a hydrocarbon, usually Diesel fuel (oil). Because of the ready availability in bulk of the raw materials, ammonium nitrate/fuel oil (ANFO) mixtures have occasionally been used for terrorist bombs, for example by the Provisional IRA and in the Oklahoma City bombing by Timothy McVeigh and Terry Nichols.

Ammonium nitrate decomposes into gases including oxygen when heated (non-explosive reaction); however, ammonium nitrate can be induced to decompose explosively by detonation. Large stockpiles of the material can be a major fire risk due to their supporting oxidation, and may also detonate, as happened in the Texas City disaster of 1947, which led to major changes in the regulations for storage and handling. A heavy explosion, with 561 casualties, occurred in the city of Oppau (on the grounds of BASF near Ludwigshafen in Germany) on September 21, 1921. Another one occurred, 80 years later, at a plant in Toulouse, France, in September 21, 2001.

Ammonium nitrate is also used in instant cold packs, as it dissolves in water endothermically, absorbing 26.2 kilojoules per mole of heat to do so.

Ammonium nitrate is also used in the treatment of titanium ores.

Industrial production is quite easy. A simple reaction of ammonia with nitric acid easily gives a solution of ammonium nitrate. Another production method is used in the so called Odda process.

Last updated: 02-03-2005 12:40:50
Last updated: 04-25-2005 03:06:01