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Ammonium nitrate



Name Ammonium nitrate
Chemical formula NH4NO3
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


ΔfH0liquid -359.6 kJ/mol
ΔfH0solid -366 kJ/mol
S0liquid, 1 bar ? J/mol·K
S0solid 151 J/mol·K


Ingestion Dangerous in large quantities.
Inhalation Very dangerous - can be fatal.
Skin May cause irritation.
Eyes May cause irritation.
More info Hazardous Chemical Database
SI units were used where possible. Unless otherwise stated, standard conditions were used.

Disclaimer and references

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 usually mixed with 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, such as in the Oklahoma City bombing.

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 hundreds of 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.