Ammonium

The ammonium ion is a positively charged ion or cation and has the chemical formula, NH₄⁺

Ammonium salts are commonly used in fertilizers. Examples of compounds containing the ammonium ion include, ammonium nitrate, NH₄NO₃ and ammonium sulfate, (NH₄)₂SO₄

All ammonium salts are soluble in water and dissociate or break down to produce aqueous ammonium ions.

eg.  ammonium nitrate ==> ammonium ion + nitrate ion

               NH₄NO₃(s) ==> NH₄⁺(aq) + NO₃^-(aq)  where aq = aqueous (surrounded by water) and s = solid

The ammonium ion is formed by the neutralization of the base ammonia, NH₃ with and acid

Ammonia + Nitric acid ==> Ammonium nitrate

NH₃ + HNO₃ ==> NH₄NO₃

Ammonia + Sulfuric acid ==> Ammonium sulfate

NH₃ + H₂SO₄ ==> (NH₄)₂SO₄

The ammonium ion has one co-ordinate covalent bond which involves the nitrogen atom donating two electrons in one of the N-H bonds.

NH₃ + H⁺ ==> NH₄⁺