oxideiodide

Oxideiodide, or oxidoiodide, is a class of inorganic compounds that contain both oxide (O2−) and iodide (I−) anions within a single chemical system. They arise when a metal cation or cation framework coordinates with oxide and iodine-containing ligands, or when oxide and iodide ions occupy distinct lattice sites in a mixed-anion solid. The term typically refers to mixed-anion compounds related to the broader family of oxyhalides, with iodide as the halide partner.

Representative oxideiodides are often layered materials in which oxide-derived cationic slabs are separated by iodide-rich layers. A well-studied example is bismuth oxyiodide, BiOI, which consists of alternating Bi2O22+ layers and I− sheets. This layered arrangement gives anisotropic physical properties and makes such materials active in visible-light absorption.

Synthesis of oxideiodides commonly involves high-temperature solid-state reactions between metal oxide precursors and iodide sources, or solvothermal routes that combine oxide and iodide in a suitable solvent with a metal salt. The exact conditions depend on the metal center and the desired stoichiometry.

Properties and applications vary with composition, but oxideiodides often exhibit semiconducting behavior with band gaps that lie in the visible range, making them attractive for photocatalysis and optoelectronic applications. BiOI, for example, is studied for photocatalytic degradation of pollutants under visible light.

See also oxyhalides; mixed-anion compounds; BiOI.