Bromine: properties, occurrence, uses and safety

Physical and chemical characteristics

Bromine is highly reactive and readily forms bromide ions (Br−) in compounds. In common chemistry it behaves as an oxidizer and participates in a range of organic and inorganic reactions. It has several oxidation states, though the −1 state (bromide) is most stable. As a diatomic molecular liquid, it vaporizes to form toxic, reddish vapors and is soluble in organic solvents; many bromine-containing compounds are volatile or reactive.

Occurrence and production

Bromine is widely distributed in the Earth’s oceans and in saline groundwater. It is typically produced industrially by oxidizing bromide-rich brines and then isolating elemental bromine by vaporization and condensation. Sea water contains bromide in low concentration; commercial sources are often natural brine wells, salt lakes or by‑products of other salt production.

Uses and applications

Bromine and bromide compounds have a variety of uses. Important applications include:

• Production of organobromine compounds used as flame retardants and plastic additives.
• Water treatment and disinfection (bromine-based sanitizers are used in pools and spas).
• Chemical synthesis: bromination is a common step in making pharmaceutical and agrochemical intermediates.
• Historical and specialty uses: silver bromide in photographic film and certain medicinal bromide salts (now less common).

History, name and notable facts

Bromine was isolated in the early 19th century by several chemists working independently. Its name derives from the Greek word for stench, reflecting the strong odor of the element. As a member of the halogen group it is closely related to chlorine and iodine but has distinct physical properties such as being liquid at near-room temperatures.

Safety and environmental considerations

Elemental bromine and many bromine compounds are toxic and corrosive; vapors can irritate eyes and airways and direct contact causes burns. Some brominated organic chemicals are persistent in the environment and have raised ecological and health concerns, so their manufacture and use are regulated in many countries. Handling bromine requires appropriate protective equipment and engineering controls to avoid exposure.