Arsenic tribromide is an inorganic molecular compound with the formula AsBr3. It is commonly described as arsenic(III) bromide and consists of arsenic bonded to three bromine atoms. As a covalent species rather than a salt in the conventional sense, it appears as colorless to pale yellow crystals and is handled mainly in small quantities in specialized chemical laboratories. For general reference see chemical compound.

Structure and basic properties

The central arsenic atom adopts a trigonal pyramidal geometry because of a stereochemically active lone pair, similar to other Group 15 trihalides. The compound is molecular in both liquid and solid forms under normal conditions and exhibits moderate volatility. It hydrolyzes on contact with water to give acidic and oxidized arsenic species and volatile hydrogen bromide, so it is not stable in moist environments. For information on the constituent elements see arsenic and bromide.

Preparation and reactions

AsBr3 can be prepared by the direct combination of elemental arsenic with bromine or by bromination of other arsenic-containing precursors. It functions as a brominating and Lewis-acidic reagent in organic and inorganic synthesis, transferring bromine or coordinating to nucleophiles. Typical reactions include hydrolysis, oxidation to higher oxidation-state species under strong oxidizing conditions, and conversion to organoarsenic derivatives. See related compounds and comparisons at analogous halides.

Uses, handling and hazards

In laboratory practice, arsenic tribromide is used as a reagent in small-scale synthesis and in research on arsenic chemistry. Its use is limited by toxicity: like most arsenic compounds it is highly poisonous, and exposures may cause severe health effects. Safe handling requires appropriate engineering controls, protective equipment, and strict waste disposal procedures. For oxidation-state context consult arsenic oxidation states.

  • Common precautions: work in a fume hood, avoid inhalation and skin contact.
  • Environmental note: arsenic compounds are persistent and potentially bioaccumulative.
  • Comparative note: AsBr3 is chemically analogous to arsenic trichloride and antimony tribromide but differs in volatility and reactivity.

Because of its hazards and specialized applications, AsBr3 appears primarily in academic and industrial research rather than routine commercial products. Proper training and regulatory compliance are essential when working with this substance.