trifluoride

Trifluoride refers to a class of chemical compounds in which three fluoride atoms are bonded to a central atom. These compounds typically have the general formulas XF3 or MF3, with the central atom being a nonmetal or metalloid such as boron or phosphorus. The bonding and molecular geometry vary with the central atom; for example, boron trifluoride (BF3) is planar and electron-deficient, while phosphorus trifluoride (PF3) is a pyramidal molecule due to a lone pair on phosphorus.

Common examples include boron trifluoride, phosphorus trifluoride, arsenic trifluoride (AsF3) and antimony trifluoride (SbF3). In addition to discrete XF3 species, many metal trifluorides, such as lanthanide trifluorides (LnF3), exist and are important in inorganic chemistry and materials science. The properties of trifluorides are strongly influenced by the central atom's electronegativity, oxidation state, and the presence of lone pairs, leading to a range of reactivities from relatively weakly bound molecules to strong Lewis acids.

Applications and relevance vary by compound. BF3 is a well-known strong Lewis acid used as a catalyst in various organic syntheses and polymerization processes. PF3 and related phosphine trifluorides act as ligands in coordination and organometallic chemistry. Some AsF3 and SbF3 derivatives serve as fluorinating reagents or catalysts in specialized chemical transformations. Safety considerations are important because many trifluorides are corrosive, toxic, and reactive with water, often releasing hydrogen fluoride or other hazardous byproducts.

See also: fluoride, Lewis acid, phosphines, metal halides.