Ammonium nitrate is a colorless solid. It dissolves in water. It makes water cold when it dissolves. It is an oxidizing agent. When it is heated gently, it turns into water and nitrous oxide. It can detonate when heated strongly. There were several disasters where ammonium nitrate exploded. Ammonium nitrate fertilizers were banned in some places because they were used to make explosives.
Ammonium nitrate is made by reacting ammonia with nitric acid. This reaction is very violent. It can be made by reacting sodium nitrate with ammonium sulfate. This makes a solution of ammonium nitrate and sodium sulfate. When the mixture is cooled, the sodium sulfate is crystallized and can be filtered.
Ammonium nitrate is used as a fertilizer. It contains more nitrogen than most fertilizers. It is also used in explosives used by terrorists. It can be used as an oxidizer in rockets.