The compounds formed by transition metals and nitrogen result when the metal is heated with N 2
or NH 3 at high temperature. Nitrogen atoms occupy interstitial position in the metals, so the “ compounds
” frequently deviate from exact stoichiometry. Rather, the composition depends on the temperature
and pressure used in the reaction. As in the case of interstitial hydrides, placing nitrogen
atoms in interstitial positions gives predictable changes in the properties of the metal. For example,
the materials are hard, brittle, high-melting, metallic-appearing solids. Some metal nitrides of this type
are important in making cutting tools and drills.