Inorganic salt, formula NH4NO3, formed from the neutralization of nitric acid by ammonia. Ammonium nitrate is a deliquescent solid with a low vapor pressure, which consequently forms in the atmosphere when high concentrations of ammonia and nitric acid occur, for example, in polluted urban areas. It is thought to sometimes make up a considerable fraction of the urban aerosol present in smog episodes. See deliquescence.

used as an explosive and fertilizer and rocket propellant

One of the main sources of artificial nitrogen fertiliser. Generally it is supplied as a prill and contains around one third of it's weight as ' nitrogen'.

component of ANFO; contents of two ships that exploded in Texas City Disaster, killing over 500 people, including all 28 volunteer firefighters at the scene.