Arsenic tribromide is an inorganic compound with the formula , it is a bromide of arsenic. This pyramidal molecule is the only known binary arsenic bromide. is noteworthy for its very high refractive index of approximately 2.3. It also has a very high diamagnetic susceptibility.CRC handbook of Chemistry and Physics, CRC Press The compound exists as colourless deliquescent crystals that fume in moist air.
Preparation Arsenic tribromide is optimally prepared by treating arsenic(III) oxide with hot concentrated hydrobromic acid.
It can also be prepared by the direct bromination of arsenic powder. Alternatively, arsenic(III) oxide can be treated with a mixture of elemental sulfur and bromine:
Arsenic tribromide hydrolyzes readily. It is soluble in hydrocarbons.
Bromides of arsenic is not known, although the corresponding phosphorus compound is well characterized. is the parent for a series of hypervalent anionic bromoarsenates including , , and .Holleman, A. F.; Wiberg, E. "Inorganic Chemistry" Academic Press: San Diego, 2001. .
Organoarsenic bromides and are formed efficiently by the copper-catalyzed reaction of methyl bromide with hot arsenic metal. This synthesis is similar to the direct process used for the synthesis of methyl chlorosilanes.
Safety Arsenic tribromide is highly toxic. It is a carcinogen and a teratogen.
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