Metalhalogenider

Metalhalogenider is a general term used to describe compounds composed of metal ions bonded to halogen elements (fluorine, chlorine, bromine, iodine). In practice, the term is often used interchangeably with metal halide in English, though metal halide more commonly denotes binary inorganic salts.

Metalhalogenider span a range of structures. They include simple binary salts MX, MX2, or MX3 formed directly from a metal and a halogen, as well as more complex coordination compounds and organometallic halides in which halide ligands coordinate to metal centers or bridge between metal atoms.

Structure and bonding vary with the metal and halogen. Many alkali and alkaline earth halides (for example NaCl, MgCl2) form highly ionic lattices with strong electrostatic interactions. Transition metal and heavier main-group halides can exhibit greater covalent character and may appear as discrete molecular species (such as TiCl4) or as polymeric networks, depending on coordination geometry and oxidation state.

Properties and applications depend on composition. Property ranges are broad, from highly volatile molecular halides to high-melting, nonvolatile ionic salts. Metalhalogenider often act as Lewis acids or catalysts (examples include AlCl3 in Friedel–Crafts chemistry) and find use in electronics, optics, and materials science. Lead or tin halides, for instance, are important in perovskite-based photovoltaics and related optoelectronic applications.

Safety and terminology notes. Many metalhalogenider are corrosive or toxic and require proper handling, storage, and ventilation. The term metalhalogenider is less common in English; metal halide is the more widely used expression for these compounds.