Stoichiometry and the structure and stability of inorganic solids

Stoichiometry (cation/anion ratio) is an important factor in determining the structure and stability of many inorganic crystals. It directly affects the coordination numbers of atoms, the relative stability of oxidation states and the tendency to form compounds with bonds between like atoms. Cation-rich binary compounds, especially oxides and nitrides, are either relatively unstable (have reduced bond energies) or do not exist. In such cases peroxides and azides are preferentially formed; these have normal bond energies.