Nitridi

Nitridi, or nitrides, are chemical compounds that contain nitrogen bonded to a more electropositive element. In binary nitrides, nitrogen combines with metals or metalloids to form materials such as aluminum nitride (AlN), gallium nitride (GaN), silicon nitride (Si3N4), and boron nitride (BN). More broadly, nitrides include ionic nitrides with nitride (N3−) ions (for example calcium nitride, Ca3N2), covalent nitrides such as BN, and transition metal nitrides that exhibit metallic bonding.

Nitrides span a range of bonding types from ionic and covalent to metallic, which leads to diverse properties. Many nitrides are refractory ceramics with high hardness, high thermal stability, and chemical resistance. They often have wide band gaps when viewed as semiconductors, such as GaN and AlN, making them important for electronic and optoelectronic devices. Some nitrides form robust ceramic networks (e.g., Si3N4) while transition metal nitrides (e.g., TiN, VN) are valued as hard coatings with good wear resistance.

Synthesis methods vary by composition and form. Binary nitrides are commonly prepared by direct reaction of nitrogen gas with the element at high temperatures or by nitriding oxides or other precursors. Thin films and devices are produced by chemical vapor deposition or molecular beam epitaxy (as in GaN and AlN). Ammonia-based nitriding and other chemical routes are used for certain nitrides and complex nitride compounds.

Applications are broad: wear-resistant ceramics and components (Si3N4), hard coatings (TiN, VN), and wide-bandgap electronics and optoelectronics (GaN, AlN, related alloys). BN is used as a lubricant and in composites, while some nitrides such as Li3N are investigated for hydrogen storage. Safety considerations include potential hydrolysis that can release ammonia, necessitating proper handling.