CXXII. Metallic carbides and nitrides of the type MX

Abstract

The structures of the metallic carbides and nitrides of the type MX with the sodium chloride structure are discussed. The view that this structure is formed in order to provide the non-metallic atom with an octahedral interstice is shown to be improbable or only part of the truth and it is considered that the face-centred cubic arrangement with the metal atoms is favoured mainly because it provides the metallic atoms with mutually perpendicular bonds to six neighbours. The melting points are discussed, and the need for further work on the electrical properties of these compounds is emphasized.