ammonium nitrate

Chem.

a white, crystalline, water-soluble powder, NH₄NO₃, usually produced by reacting nitric acid with vaporous ammonia: used chiefly in explosives, fertilizers, freezing mixtures, and in the manufacture of nitrous oxide.

[1880-85]

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▪ chemical compound

      (NH₄NO₃), a salt of ammonia and nitric acid, used widely in fertilizers and explosives. The commercial grade contains about 33.5 percent nitrogen, all of which is in forms utilizable by plants; it is the most common nitrogenous component of artificial fertilizers (fertilizer). Ammonium nitrate also is employed to modify the detonation rate of other explosives, such as nitroglycerin in the so-called ammonia dynamites, or as an oxidizing agent in the ammonals, which are mixtures of ammonium nitrate and powdered aluminum.

      Ammonium nitrate is a colourless, crystalline substance (melting point 169.6° C [337.3° F]). It is highly soluble in water; heating of the water solution decomposes the salt to nitrous oxide (laughing gas). Because solid ammonium nitrate can undergo explosive decomposition when heated in a confined space, government regulations have been imposed on its shipment and storage.

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