1.   A complex ion consists of a central atom to which are bonded atoms, ions or groups of atoms.

2.   The formula of the complex ion is enclosed in square brackets.

3.   In naming complex ions, the names of the ligands are cited first.

4.   The name of the complex ion terminates with the name of the metal together with the oxidation state of the metal in parentheses.

5.   Hydrochloric acid secretion by gastric parietal cells entails complex ion transport events at the apical membrane.