Bromine, like chlorine, fluorine and iodine, is one of the elements in the chemical group known as “halogens”.
Bromine was not discovered as a chemical element until 1826, when the French chemist Antoine Balard isolated it from chlorine. Bromine in its elemental form is a highly volatile reddish-brown liquid at room temperature.
However, bromine is never found in its elemental form naturally, but in compounds with other substances, known as bromides and which are used as the raw material to produce commercial brominated products.
Bromine is abundant in nature as bromide salts or as organobromine compounds, which are produced by many types or marine organisms. The most recoverable form of bromine is from soluble salts found in seawater, salt lakes, inland seas, and brine wells. Sea water contains bromine in about 65 part per million (ppm) but bromine is found in much higher concentrations (2500 to 10,000 ppm) in inland seas and brine wells. The major areas of bromine production in the world are from salt brines found in the United Stated and China, from the Dead Sea in Israel and Jordan and from ocean water in Wales and Japan. Bromine is also present in rock and the earth's crust.
Applications of Bromine
Since bromine was first discovered, various bromine compounds have been put to important use.
One of the major uses of bromine is a water purifier/disinfectant, as an alternative to chlorine. Brominated compounds are used for water treatment in swimming pools and hot tubs and are also used to control algae and bacterial growth in industrial processes.
Bromine compounds are effective pesticides, used both as soil fumigants in agriculture, particularly fruit-growing, and as a fumigant to prevent pests from attacking stored grain and other produce. Significant volumes of world trade in agriculture goods depend on the use of bromine compounds to ensure compliance with mandatory rules on quarantine. Bromine compounds are also used as intermediates to make some of the agriculture chemicals we take for granted.
Cars - Past and Future
In the past, bromine compounds were used in leaded fuel, as a constituent of “anti-knock fluid”. However, this use has dramatically declined as lead has gradually been removed from fuel. Bromine compounds are now being tested in batteries for electric cars, designed to produce zero emissions. Such batteries can also be used as electricity storage devices.
A key use of bromine compounds is in the manufacture of pharmaceuticals. Brominated substances are important ingredients of many over-the-counter and prescription drugs, including analgesics, sedatives, and antihistamines. Some of the drugs have also proved effective in the treatment of pneumonia, and cocaine addiction. Currently, pharmaceuticals, that use bromine compounds in their manufacture, are undergoing trials for treatment of Alzheimer's disease, and new generations of anti-cancer and AIDS drugs.
Bromine compounds have a number of applications in photography. Several compounds are used to make the all-important light-sensitive component of a photographic emulsion - without these bromine compounds your pictures would not capture sufficient light. Other bromine compounds are used as an ingredient in photo development - without which your pictures would not be able to be developed.
Brominated Flames Retardants (BFRs)
However, the largest use - and most important life safety benefit - of bromine is in brominated flame retardants.