weights increase. (Can occur with X= H, F, Cl, Br, and I) 2 SiBr4 + 2 SiCl4 → SiBr3Cl + 2 SiBr2Cl2 + SiBrCl3 Si2Cl6 + Si2Br6 → Si2ClnBr6−n Silicon tetrabromide hydrolyzes readily when exposed to air causing it to fume: SiBr4 + 2 H2O → SiO2 + 4 HBr Silicon tetrabromide is stable in the presence of oxygen at room temperature, but bromosiloxanes form at 670–695 ˚C . 2 SiBr4 + 1⁄2 O2 → Br3SiOSiBr3 + Br2 Uses Due to its close similarity to silicon tetrachloride, there are few applications unique to SiBr4. The pyrolysis of SiBr4 does have the advantage of depositing silicon at faster rates than that of SiCl4, however SiCl4 is usually preferred due to its availability in high purity. Pyrolysis of SiBr4 followed by treatment with ammonia yields silicon nitride (Si3N4) coatings, a hard compound used for ceramics, sealants, and the production of many cutting tools. References Bromides Inorganic silicon compounds