Nitriden

Nitriden, in English generally called nitrides, are a class of chemical compounds composed primarily of nitrogen bonded to a less electronegative element. They span a wide range of bonding types, from predominantly ionic compounds such as lithium nitride to covalent materials like silicon nitride and boron nitride, as well as transition-metal nitrides with mixed bonding character.

The structure and properties of nitriden vary with composition. Ionic nitrides, such as Li3N, feature N3− anions in a lattice with metal cations. Covalent nitriden, including silicon nitride (Si3N4) and boron nitride (BN), form strong covalent networks contributing to hardness and thermal stability. Metallic or transition-metal nitriden, such as titanium nitride (TiN) or vanadium nitride (VN), often exhibit high hardness, good electrical conductivity, and chemical inertness.

Synthesis methods include direct nitridation of elements at high temperatures, reaction of metals with nitrogen sources, and chemical vapor deposition or other thin-film techniques for coatings. Nitriden typically display high melting points and wide band gaps, making them suitable for extreme-temperature applications, protective coatings, and ceramic materials.

Applications are broad. Hardened coatings like TiN, VN, and CrN are used to reduce wear in tools. Semiconductor nitrides, including gallium nitride (GaN) and aluminum nitride (AlN), enable optoelectronics and high-frequency devices. Ceramic nitrides such as silicon nitride (Si3N4) and aluminum nitride (AlN) are valued for their mechanical strength, thermal conductivity, and insulation properties.

Natural occurrence of nitriden is rare; osbornite ( TiN-rich) is a notable natural nitride mineral found in meteorites. Some nitriden can react with water or moisture, releasing ammonia in certain cases, so handling requires appropriate precautions.