Ammonium nitrate
General
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|---|---|
| Name | Ammonium nitrate |
| Chemical formula | NH4NO3 |
| Appearance | White solid |
Physical Attributes
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| Formula weight | 80.0 amu |
| Melting point | 442 K (169 °C) |
| Boiling point | decomposes at 483 K (210 °C) |
| Density | 1.7 ×103 k/m3 |
| Crystal structure | ? |
| Solubility | 208 g in 100g water |
Thermochemistry
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| ΔfH0liquid | -359.6 kJ/mol |
| ΔfH0solid | -366 kJ/mol |
| S0liquid, 1 bar | ? J/mol·K |
| S0solid | 151 J/mol·K |
Safety
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| 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. | |
The chemical compound ammonium nitrate, the nitrate of ammonium 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. Another 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.
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.
