oxychloride

Oxychloride is a class of inorganic compounds that contain both oxide (O2−) and chloride (Cl−) ligands bound to a central metal atom. These compounds are often described as metal oxychlorides and can have formulas such as MOCl2, MOCl, or more complex MxOyClz, depending on composition and structure. The defining feature is the coexistence of oxide and chloride within the same compound, giving distinctive bonding and structural motifs.

In many oxychlorides, the metal is in a relatively high oxidation state to balance the charges of oxide and chloride ligands. Structures can be monomeric or polymeric, and the coordination geometry around the metal is frequently distorted, commonly approaching octahedral or square-pyramidal arrangements. Oxo groups may bridge between metal centers, contributing to layered or networked architectures.

Synthesis of oxychlorides typically involves partial chlorination or hydrolysis of metal oxides, or controlled oxidation of metal chlorides in the presence of oxide sources. They can also arise from selective reactions of metal halides with water or hydrogen chloride under specific conditions. Due to their mixed ligand environment, these compounds often exhibit sensitivity to air and moisture and may be obtained as crystalline solids with characteristic colors.

Applications and roles: metal oxychlorides serve as precursors to other inorganic materials, including metal oxides, and are used in catalysis or materials synthesis. They are studied for their structural relationships between oxide and chloride ligands and for insights into tuning properties of related compounds.

Examples include iron(III) oxychloride (FeOCl), titanium(IV) oxychloride (TiOCl2), vanadium(IV) oxychloride (VOCl2), and zinc oxychloride (ZnOCl2).