The formula for nitride ion is N3?. The term nitride ion refers to any chemical compound containing nitrogen ions that have a negative-three oxidation state.
Examples of such compounds are titanium nitride, calcium nitride, boron nitride and silicon nitride. Due to its ionic charge, the ion is rarely found out of solution in nature. Because it carries a heavy negative ionic charge, the ion N^-3 will readily pick up a loose proton or bond with another element or compound that has a positive charge. Nitrides are resistant to heat, or refractory. For this reason, nitrides are used in high-heat, high-corrosion and high-impact applications such as kilns, heat shields and precision tools.