Vanadium Mononitride, VN

Vanadium Mononitride, VN, can be prepared synthetically, but it is more conveniently prepared by calcining ammonium metavanadate, NH₄VO₃, in air, and heating the black residue to a white heat in a current of dry ammonia. It has also been obtained by the action of dry ammonia gas on vanadium oxytrichloride, VOCl₃, and by heating a mixture of vanadous oxide, V₂O₃, and carbon at 1200° C. in an atmosphere of nitrogen. It is a greyish-brown powder which melts with decomposition at 2050° C. Its density is 5.91. The electrical conductivity, magnetic susceptibility, and crystal structure have been investigated, and the dissociation pressures and calculated heat of formation are given by Slade and Higson. Vanadium mononitride i s a very stable compound; it yields vanadium pentoxide only on being very strongly heated in air. It evolves ammonia on being treated with steam at 400° C., when heated with soda-lime or when boiled with caustic potash solution. Nitric acid dissolves it, but hydrochloric acid and sulphuric acid are without action.