Niobium Mononitride, NbN

Niobium Mononitride, NbN, is obtained by heating a mixture of niobium pentoxide and lampblack in an atmosphere of nitrogen at temperatures between 1200° and 1300° C. It is a bright grey powder with a yellowish lustre, melting at 2300° abs.; density 8.4. The specific electrical resistance is 2×10^-4 ohms per cc. at room teftiperature and 4.5×10^-4 ohms per cc. at the melting-point. It is insoluble in all acids and in aqua-regia. On being heated it loses much of its nitrogen content, even when heated in an atmosphere of nitrogen. When heated either in air or mixed with copper oxide it forms niobium pentoxide. Its crystal structure has been studied by the Debye-Scherrer method.