Ammonium Nitrate

Products

Ammonium nitrate is available as a pure substance in specialty stores. It is included in instant refrigerated bags sold as medical devices. Some products also contain calcium ammonium nitrate.

Structure and properties

Ammonium nitrate (NH4NO3, Mr = 80.04 g/mol) exists as a white, crystalline, and odorless powder that is readily soluble in water.

  • Structure: NH4+NO3

Ammonium nitrate is prepared with ammonia and the nitric acid (strongly exothermic acid-base reaction):

  • NH3 + HNO3 NH4NO3

Effects

Ammonium nitrate has oxidizing and oxidizing properties. When heated, it produces nitrous oxide and water:

  • Heating: NH4NO3 N2O + 2 H2O

As an explosive:

  • 2 NH4NO3 2 N2 + O2 + 4 H2O

When ammonium nitrate is dissolved in water, the temperature drops because the process is endothermic. This effect is exploited for the production of instant cooling bags.

Areas of application

  • For instant refrigerated bags.
  • For fertilizer (nitrogen fertilizer).
  • As a reagent.
  • For the civilian production of explosives and fireworks.
  • For chemical experiments, to demonstrate the endothermic solution.

Abuse

Ammonium nitrate can be misused for the illegal manufacture of explosives. It has been used in several terrorist attacks in the past, for example in Oklahoma City in 1995 or Oslo in 2011. Ammonium nitrate is one of the precursors for explosives.

Adverse effects

Ammonium nitrate has oxidizing properties and can cause severe eye irritation if accidental contact occurs. Especially when mixed with other materials, it may explode if heated.