Titanium Cyanonitride

Very hard cubical crystals of a bright copper colour are sometimes found in the cavities of cast-iron and slag obtained by the smelting of titaniferous iron ore in the blastfurnace. This substance was mistaken by Wollaston for metallic titanium, but Wohler proved that it contained carbon and nitrogen, and attributed to it the formula Ti(CN)₂.3Ti₃N₂. Wohler also obtained this substance artificially by strongly heating in a closed crucible a mixture of potassium ferrocyanide and titanic oxide, and by bringing titanium tetrachloride vapour into contact with fused potassium cyanide; it is also formed when a stream of nitrogen is passed over a white-hot mixture of titanic oxide and charcoal. Cyanonitride of titanium has a density of 5.28 (Wollaston) or of 4.1 to 5.1. It is unattacked by boiling nitric or sulphuric acid, but easily dissolved by a mixture of nitric and hydrofluoric acids. That it contains the cyanogen radicle is shown by the fact that when heated in a current of chlorine it forms a compound of titanium tetrachloride and cyanogen chloride, CNCl, which appears as a sublimate, and when ignited in a current of steam yields hydrogen, hydrogen cyanide and ammonia, leaving a residue of titanic oxide. When this substance is fused with potash, ammonia is evolved and titanate formed. Its composition cannot be regarded as settled; whether it is really titanium "cyanonitride" or a mixture of carbide and nitride may even be uncertain, though it differs from nitride in yielding the TiCl₄ - CNCl compound when heated with chlorine.