Bromine

Bromine is a reactive nonmetal in the halogen family, which also includes chlorine and iodine. It is a reddish-brown liquid at room temperature and readily gives off similarly colored vapor. In nature, it occurs mainly as bromide salts dissolved in seawater and concentrated brines, rather than as the pure element. Industry recovers bromine from salt-lake and underground brines by using chlorine to release it from bromide, then collecting and purifying it. Some bromine-containing compounds serve as flame retardants in plastics by interrupting the chemical reactions that keep a fire burning. Another compound, silver bromide, responds to light and is used in photographic film.