HBr

Hydrogen bromide (HBr) is a diatomic molecule that forms hydrobromic acid when dissolved in water. In the gas phase it is a colorless, corrosive gas with a sharp, pungent odor. It readily dissolves in water to give hydrobromic acid, a strong mineral acid that dissociates to provide a high concentration of bromide ions in solution.

Industrial production of HBr is typically achieved by direct combination of hydrogen and bromine: H2 + Br2 → 2 HBr, usually at elevated temperatures. An alternative route is the generation of HBr gas from bromide salts and strong acids, followed by absorption in water to form hydrobromic acid.

Applications include use as a brominating agent in organic synthesis. Hydrobromic acid converts alcohols to alkyl bromides and adds to alkenes to yield alkyl bromides via Markovnikov-type addition. It serves in the preparation of brominated intermediates for pharmaceuticals, agrochemicals, and specialty chemicals.

Safety: HBr is highly corrosive and irritating to skin, eyes, and the respiratory tract. It releases fumes that can form hydrobromic acid on contact with moisture. It reacts with many materials, particularly metals and oxidizers. It should be stored in corrosion-resistant containers, used in a well-ventilated area or fume hood, and handled with appropriate personal protective equipment.