Antimony tribromide explained

Antimony tribromide (SbBr₃) is a chemical compound containing antimony in its +3 oxidation state.

Production

Antimony tribromide may be made by the reaction of antimony with elemental bromine, or by the reaction of antimony trioxide with hydrobromic acid.

Alternatively, it can be prepared by the action of bromine on a mixture of antimony sulfide and antimony trioxide at 250 °C.

Chemical properties

Antimony tribromide has two crystalline forms, both having orthorhombic symmetries. When a warm carbon disulfide solution of SbBr₃ is rapidly cooled, it crystallizes into the needle-like α-SbBr₃, which then slowly converts to the more stable β form.^[1]

Antimony tribromide hydrolyzes in water to form hydrobromic acid and antimony trioxide:

2 SbBr₃ + 3 H₂O → Sb₂O₃ + 6 HBr

Uses

It can be added to polymers such as polyethylene as a fire retardant.^[2] It is also used in the production of other antimony compounds, in chemical analysis, as a mordant, and in dyeing.^[3]

References

1. 10.1246/bcsj.43.2398. Structural Studies of Antimony Tribromide and Its Molecular Complex with Benzene by Means of the 81Br Nuclear Quadrupole Resonance. 1970. Okuda, Tsutomu. Bulletin of the Chemical Society of Japan. 43. 2398. Terao. Hiromitsu. Ege. Osamu. Negita. Hisao. 8.
2. Yang . Y. P. . D. G. Brewer . J. E. S. Venart . 1991 . A study of the synergistic action of antimony oxide in fire-retardant polyethylene . Fire and Materials . 15 . 37–42 . 10.1002/fam.810150107 .
3. "Antimony tribromide" http://cameochemicals.noaa.gov/chemical/2501