Tantalum Mononitride, TaN

Tantalum Mononitride, TaN, has been prepared by heating the metal first in hydrogen and then in nitrogen, or by the action of hydrogen and nitrogen on tantalum pentachloride vapour. It is a dark blue or black substance which melts at 3070° abs. with some loss of nitrogen. Its dissociation pressures have been studied. Density = 14.1. Direct heating of tantalum in nitrogen has also given rise to a black dinitride, TaN₂, which is not attacked by concentrated hydrochloric, nitric or sulphuric acids. It evolves ammonia when fused with caustic alkalis, and burns with incandescence to the pentoxide when heated in air.