The greatest use of bromine is in the manufacture of ethylene bromide which enters in antiknock fluids for motor fuels. Lesser amounts of bromine are used to prepare a great variety of other organic and inorganic compounds. Bromine is an excellent bleaching and sanitizing agent and, as a liquid, is used as a reagent for analytical and synthetic purposes. The pure cesium bromide so obtained has been used in manufacturing optical prisms which are highly transparent to infrared radiation.
The bromides of the alkali and alkaline earth elements find usage in pharmacy because of their sedative actions, in photography for preparing silver bromide emulsions, and in the industrial drying of air as desiccants.
The major use for methyl bromide lies in the extermination of insect and rodent pests. Bromochloromethane and bromodifluoromethane are used as fire-extinguisher fluids.