Nitrides

Nitrides are binary compounds formed between nitrogen and elements that are more electropositive. In inorganic chemistry, nitrides often contain the nitride anion, N3-, in ionic nitrides, while covalently bonded nitrides also occur (for example, boron nitride). The term covers a wide range of materials, including transition metal nitrides, main-group nitrides, covalent nitrides, and rare-earth nitrides.

Metal nitrides, such as titanium nitride (TiN), vanadium nitride (VN), and chromium nitride (CrN), are typically hard, refractory ceramics with high melting points. They are widely used as protective coatings to improve wear resistance and reduce friction. Main-group nitrides, including aluminum nitride (AlN) and gallium nitride (GaN), span ceramic insulators and wide-bandgap semiconductors. Silicon nitride (Si3N4) is a strong, heat‑resistant ceramic used in engines and bearings, while GaN and related alloys are foundational for LEDs and power electronics. Covalent nitrides like boron nitride (BN) also play important roles in lubricants, composites, and as insulating materials.

Synthesis methods vary: direct nitridation of elements at high temperature in nitrogen-containing atmospheres; solid-state reactions; and various deposition techniques such as chemical vapor deposition (CVD) or physical vapor deposition (PVD) to form coatings. Some nitrides are prepared through nitridation of precursors or by reactions in ammonia or other nitrogen sources.

Properties of nitrides are diverse. They often exhibit high hardness, high thermal stability, and good chemical resistance, but electrical behavior ranges from insulating (AlN, Si3N4) to semiconducting (GaN) and even metallic in some transition-metal nitrides. Many nitrides are moisture-sensitive and can hydrolyze in water, releasing ammonia, so handling and storage practices vary by material.

Common examples include TiN, VN, CrN, AlN, Si3N4, GaN, and BN.