Higher metal nitrides: current state and prospects

The review integrates and systematizes data published in the last 15 years on the physicochemical characteristics of specific chemical compounds formed by metal elements with nitrogen atoms containing three or more nitrogen atoms per metal atom. Most often, the total number of nitrogen atoms exceeds their greatest number allowed by the formal higher oxidation state of the metal atom present in the compound. The conceptual possibility of practical application of these compounds now and in the future is also discussed.The bibliography includes 230 references.