Tungsten hexabromide

Tungsten hexabromide, also known as tungsten(VI) bromide, is a chemical compound of tungsten and bromine with the formula WBr6. It is an air-sensitive dark grey powder that decomposes above 200 °C to tungsten(V) bromide and bromine.

Production and reactions
Tungsten hexabromide is mainly produced by the reaction of metallic tungsten and bromine at temperatures around 100 °C in a nitrogen atmosphere:
 * W + 3 Br2 → WBr6

Another method of producing this compound is by the reaction of tungsten hexacarbonyl and bromine at room temperature, releasing carbon monoxide. It can also be produced by the metathesis reaction of boron tribromide and tungsten hexachloride.

WBr6 is reduced with elemental antimony at elevated temperatrues, consecutively producing, WBr5, WBr4, W4Br10, W5Br12, then finally WBr2 at 350 °C. This reaction produces antimony tribromide as a side product. Any of these bromides can be reverted to the hexabromide by oxidation with bromine at 160 °C.

Tungsten hexabromide is hydrolyzed in water, producing tungsten pentoxide and releasing bromine.

Tungsten(VI) oxytetrabromide is produced by the reaction of tungsten hexabromide and tungsten(VI) oxide:
 * 2 WBr6 + WO3 → 3 WOBr4

Structure
The trigonal crystal structure of WBr6 consists of isolated WBr6 octahedra and is isostructural with α-WCl6.