Zirconium Nitrides

Zirconium does not combine with nitrogen so readily as titanium. Three nitrides, however, have been described: Zr₃N₂, Zr₂N₃, and Zr₃N₈; but Wedekind appears recently to recognise the existence of only one nitride, viz. Zr₃N₂.

Zr₃N₂ is formed as a red-brass crystalline powder, of density 6.75, when the metal is heated to 1050° C. in a current of nitrogen or to 1000° C. in ammonia gas; it is very stable towards oxygen and chlorine, but evolves ammonia when fused with potash.

Zr₂N₃ and Zr₃N₈. - By heating a mixture of amorphous zirconium with aluminium to a white heat in the air Mallet obtained a product which evolved ammonia when fused with potash; and similar products were obtained by heating the metal or its chloride in ammonia. More definite knowledge was gained later by Matthews, who obtained Zr₃N₈ as a grey product by heating ZrCl₄.8NH₃ in a current of nitrogen; and Zr₂N₃, which was similar in appearance, by heating the tetrachloride in a stream of ammonia. Wedekind also obtained Zr₂N₃ in bronze-coloured microscopic crystals by reducing zirconia with magnesium in a loosely covered crucible and washing away the colloidal metal; the same nitride is also formed when the carbide is heated in a current of nitrogen. Both these nitrides are soluble in hydrofluoric acid.