All of the ammonium salts decompose, or break down upon heating at a molecular level. Another property of ammonium salts is that they have solubility in water. They dissolve in water and can be used for many different things. Ammonium chloride salt can be used for cleaning metal surfaces before soldering. One use of Ammonium Sulphate is use as a fertiliser. Ammonium nitrate is used in the manufacture of fire works, and ammonium carbonate is used as a smelling salt.
Other than the ability to decompose upon heating, it is also soluble (dissolve) in water. It reacts with alkalis to give off ammonia gas. It can also be a source of nutrients for plants to grow but can be toxic given in high concentration, and can cause death. It is toxic to crops and is rarely applied directly.