Oxidenitrides

Oxidenitrides are a class of compounds that contain both oxide (O2−) and nitride (N3−) anions within a single crystalline lattice. They are a subset of mixed-anion materials in which two different anions coexist in a solid, allowing a combination of properties characteristic of oxides and nitrides.

Structurally, oxidenitrides can be described by general formulas such as MxOyNz, where the cation species balance the charges and the relative amounts of oxygen and nitrogen can vary. The anion sublattice may be ordered or disordered, and the surrounding cation framework adapts to accommodate the mixed anions. This structural flexibility enables tuning of physical properties across a range of compositions.

Synthesis methods for oxidenitrides typically involve nitriding or ammonolysis of oxide precursors, high-temperature reactions of oxides with ammonia or nitrogen, or deposition techniques such as chemical vapor deposition and other solid-state routes. Careful control of temperature, atmosphere, and composition allows adjustment of the O/N ratio and the resulting material properties.

Properties of oxidenitrides often reflect a balance between oxide and nitride characteristics. They can exhibit high thermal stability and chemical robustness, wider band gaps than many oxides, and tunable optical, electronic, or catalytic properties. Applications span transparent ceramics, protective coatings, optoelectronic and photocatalytic materials, and components in solid-state devices where mixed-anion chemistry offers advantageous performance.

A well-known example is aluminum oxynitride (AlON), a ceramic that blends oxide and nitride components and is valued for its hardness and optical transparency. Other oxidenitrides, including various metal oxynitrides and silicon- or germanium-based systems, are studied for optical, electronic, and catalytic applications.