Overview
Antimony pentachloride is a chemical compound commonly written as SbCl5. It is a pentahalide of antimony in the +5 oxidation state and exists as a discrete molecular species under many conditions. The substance is a powerful Lewis acid and readily accepts electron pairs, which underpins much of its chemical behavior and practical utility. For its basic description and identifiers see compound data.
Structure and properties
The molecule consists of an antimony atom coordinated to five chlorine atoms in a geometry that is best described by a trigonal bipyramid arrangement. As a dense, volatile liquid at ambient conditions it has a characteristically pungent, corrosive fume when exposed to moist air because it hydrolyzes to give hydrochloric acid and antimony oxychloride species. Its strong affinity for electron donors leads it to form stable adducts and complex anions, such as hexachloroantimonate, in the presence of additional chloride sources; examples and spectral data are available through chemical reference sources like reference entries.
Preparation and reactions
Antimony pentachloride is produced by direct chlorination of elemental antimony or by oxidation of lower-valent antimony chlorides with chlorine or other chlorinating agents. It reacts vigorously with water and nucleophiles, releasing HCl and producing oxo- and oxychloride products. In organic chemistry it can act as a chlorinating reagent, oxidant and catalyst for electrophilic substitution or polymerization reactions. Its reactivity with ethers, alcohols and hydrocarbons is guided by its Lewis acidity and tendency to form coordination complexes; see general reaction summaries at reaction overview.
Uses and examples
Applications rely on the compound's ability to accept electron density and to generate electrophilic chlorine:
- As a Lewis-acid catalyst in organic synthesis and polymer chemistry.
- As a chlorinating or oxidizing agent for specialized transformations in laboratory and industrial chemistry.
- As a precursor to anions and salts used in ionic liquids and coordination compounds.
Safety and distinctions
SbCl5 is highly corrosive and toxic; it reacts violently with water and must be handled under inert, dry conditions with appropriate protective equipment. It is distinct from antimony trichloride (SbCl3), which contains antimony in the +3 state and shows different volatility, reactivity and coordination chemistry. For safety data, storage and disposal guidelines refer to authoritative safety documentation and databases: safety information.