Bromine
Bromine is a chemical element with the symbol Br and atomic number 35. It is the only nonmetallic element that is liquid near room temperature, a reactive halogen found mostly as bromide salts in nature, and an important chemical in flame retardants, drilling fluids, photography, pharmaceuticals, and water treatment.
What bromine is
Bromine is a halogen element. Elemental bromine usually exists as Br2, a molecule made from two bromine atoms. Near room temperature it is a dense red-brown liquid that gives off irritating reddish vapor. Because it is reactive and corrosive, elemental bromine is handled mainly in controlled industrial or laboratory settings.
Bromine versus bromide
Bromine and bromide are related but different. Bromine, Br2, is elemental bromine and is hazardous. Bromide, Br-, is a negatively charged ion found in salts, seawater, brines, and minerals. Many useful bromine chemicals begin from bromide resources, but their properties depend on the full compound, not only the presence of bromine.
Where bromine comes from
Bromine is not found freely in nature because it reacts readily. Commercial bromine is usually produced from bromide-rich brines, seawater, salt lakes, or underground deposits. Chlorine is often used industrially to oxidize bromide ions into elemental bromine, which can then be separated and converted into other compounds.
Chemistry and the halogens
Bromine sits below chlorine and above iodine in Group 17 of the periodic table. It is generally less reactive than chlorine but more reactive than iodine. This middle position makes bromine chemistry useful for substitution reactions, flame-retardant compounds, pharmaceuticals, and specialized materials.
Uses
Bromine compounds are used in flame retardants, oil and gas drilling fluids, water treatment chemicals, photographic silver bromide, medicines, dyes, agricultural chemicals, and some battery chemistries. Several uses have changed over time as health and environmental concerns have led to restrictions or substitutions for certain brominated compounds.
Flame retardants
Some brominated compounds slow ignition or flame spread by interfering with combustion chemistry. They have been used in electronics, textiles, plastics, and building materials. This usefulness comes with tradeoffs: certain brominated flame retardants can persist in the environment, accumulate in organisms, or raise toxicity concerns.
Water and disinfection
Bromine-based disinfectants are used in some pools, spas, cooling towers, and industrial water systems. Bromine chemistry differs from chlorine chemistry, especially in warm water and certain pH conditions. As with chlorine, disinfectant strength, byproducts, exposure, and safe handling all matter.
Safety
Elemental bromine can burn skin, irritate eyes and airways, and damage lungs if inhaled. It is corrosive, volatile, and toxic. Safe handling requires compatible containers, ventilation, protective equipment, emergency planning, and careful separation from reactive materials. Bromide salts and organic bromine compounds have different hazards and should be assessed individually.
Why it matters
Bromine matters because it is chemically versatile and environmentally consequential. It supports useful products and industrial processes, but some brominated chemicals have created long-lasting pollution and health questions. Understanding bromine helps distinguish elemental hazards, ordinary bromides, useful specialty chemistry, and compounds that need tighter control.