Tribromoborane, Boron bromide
3D model (JSmol)
CompTox Dashboard (EPA)
|Molar mass||250.52 g·mol−1|
|Appearance||Colorless to amber liquid|
|Odor||Sharp and irritating|
|Melting point||−46.3 °C (−51.3 °F; 226.8 K)|
|Boiling point||91.3 °C (196.3 °F; 364.4 K)|
|Reacts violently with water|
|Solubility||Soluble in ethanol, CCl4|
|Vapor pressure||7.2 kPa (20 °C)|
Refractive index (nD)
|Viscosity||7.31 x 10−4 Pa s (20 °C)|
Heat capacity (C)
|228 J/mol K|
Std enthalpy of
|Main hazards||Reacts violently with water, potassium, sodium, and alcohols; attacks metals, wood, and rubber|
|Safety data sheet||ICSC 0230|
|GHS signal word||DANGER|
|H330, H300, H314 Within the European Union, the following additional hazard statement (EUH014) must also be displayed on labeling: Reacts violently with water.|
|US health exposure limits (NIOSH):|
|C 1 ppm (10 mg/m3)|
IDLH (Immediate danger)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
|what is ?)(|
Boron tribromide, BBr3, is a colorless, fuming liquid compound containing boron and bromine. Commercial samples usually are amber to red/brown, due to weak bromine contamination. It is decomposed by water and alcohols.
Boron tribromide is commercially available and is a strong Lewis acid.
The mechanism of dealkylation of tertiary alkyl ethers proceeds via the formation of a complex between the boron center and the ether oxygen followed by the elimination of an alkyl bromide to yield a dibromo(organo)borane.
Aryl methyl ethers (as well as activated primary alkyl ethers), on the other hand are dealkylated through a bimolecular mechanism involving two BBr3-ether adducts.
The electronics industry uses boron tribromide as a boron source in pre-deposition processes for doping in the manufacture of semiconductors. Boron tribromide also mediates the dealkylation of aryl alkyl ethers, for example demethylation of 3,4-dimethoxystyrene into 3,4-dihydroxystyrene.
The first synthesis was done by M. Poggiale in 1846 by reacting boron trioxide with carbon and bromine at high temperatures:
Boron tribromide is used in organic synthesis, pharmaceutical manufacturing, image processing, semiconductor doping, semiconductor plasma etching, and photovoltaic manufacturing.