halogenide

Halogenide, often used interchangeably with halide, refers to compounds that contain a halogen element (fluorine, chlorine, bromine, iodine, or astatine) bonded to another element. The halide ion X− is the most common form, produced when a halogen gains an electron, as in NaCl or CaBr2. Halogenide chemistry covers inorganic salts and organohalogen compounds with carbon or other atoms.

In inorganic halides, alkali and alkaline earth salts such as NaF, NaCl, KBr, and CaCl2 are typical. These compounds are usually ionic solids with high melting points; solubility in water varies. Halides are widely used in industry and daily life—table salt, toothpaste fluoride, and fluxes are examples. Reactions include halide exchange and hydrolysis; some heavy metal halides are sensitive or toxic.

Organohalogens are carbon-bound halogens, including alkyl chlorides (chloromethane, tert-butyl chloride) and aryl iodides. They are central to organic synthesis, enabling nucleophilic substitution and cross-coupling reactions (for example, Suzuki and Heck reactions). Many organohalogens are persistent environmental pollutants, requiring careful management and regulation.

Halide minerals occur naturally, with examples such as halite (sodium chloride) and fluorite (calcium fluoride). In mineralogy, halides refer to minerals containing halide anions paired with metals. The term halogenide is less common in modern usage but appears in some contexts to denote ionic halide salts or halogen-containing species. See also halide ion, hydrogen halide, and interhalogen compounds.