BiBr3

BiBr3, or bismuth tribromide, is an inorganic compound composed of bismuth in the +3 oxidation state and bromine. It is usually encountered as a moisture‑sensitive crystalline solid that hydrolyzes in water to give hydrobromic acid and oxybromide species such as BiOBr.

BiBr3 can be prepared by direct bromination of bismuth metal: 2 Bi + 3 Br2 → 2 BiBr3. It can also be obtained by treating Bi2O3 with hydrobromic acid and bromine. In the solid state, BiBr3 forms a polymeric network with Bi centers linked by bromide bridges; in the gas phase the molecule is believed to be monomeric.

In solution, especially in the presence of excess bromide, BiBr3 forms bromo-bismuthate complexes such as [BiBr6]3−, reflecting the coordination flexibility of bismuth(III). It acts as a Lewis acid and forms adducts with donors such as pyridine, phosphines, or ethers.

BiBr3 is mainly used as a reagent in inorganic and organic synthesis, including as a Lewis acid catalyst and as a precursor for bismuth-containing materials and organobismuth compounds. It has applications in preparing bismuth-based halide materials and in broader metal halide chemistry.

BiBr3 is corrosive and toxic if ingested or inhaled; hydrolysis releases hydrobromic acid, and exposure should be avoided. It should be handled in a dry, well-ventilated facility with appropriate protective equipment.