Boron nitride is a chemical compound with chemical formula BN, consisting of equal numbers of boron and nitrogen atoms. BN is isoelectronic to a similarly structured carbon lattice and thus exist in various crystalline forms. The hexagonal form corresponding to graphite is the most stable and softest among BN polymorphs, and is therefore used as lubricant and an additive to cosmetic products.

Beta carbon nitride (β-C3N4) is a material predicted to be harder than diamond.[1]The material was first proposed in 1985 by marvin cohen and amy liu. Examining the nature of crystalline bonds they theorized that carbon and nitrogen atoms could form a particularly short and strong bond in a stable crystal lattice in a ratio of 1:1.3.

The Fe-silicon nitride synthesized by flashing combustion process was studied to determine the reaction temperature between Fe and silicon nitride, the account of N2 given out in the course of the reaction, and the change of the microstructure during calcination.

Gallium nitride (GaN) is a very hard material commonly used in bright LEDs since the 1990s. The compound is a direct-band gap semiconductor material of quartzite crystal structure, with a wide (3.4 ev) band gap, used in optoelectronic, high-power and high-frequency devices.

Silicon nitride (Si3N4) is a chemical compound of silicon and nitrogen. It is a hard ceramic having high strength over a broad temperature range, moderate thermal conductivity, low coefficient of thermal expansion, moderately high elastic modulus, and unusually high fracture toughness for a ceramic.

Magnesium nitride, Mg3N2, is an inorganic compound of magnesium and nitrogen. At room temperature and pressure it is a greenish yellow powder. It reacts with water to produce ammonia gas, as do many metal nitrides.