bromine series is a chemical element with the symbol Br and an atomic number 35. It is a fuming red-brown liquid at room temperature. Organic bromine compounds are easily dissociated to generate free bromine atoms at high temperatures, which is a process that blocks the free radical chemical chain reactions. This effect makes the organic bromine compounds useful as flame retardants, with more than half of the bromines produced annually in the world are used for this purpose. Bromine compounds are also used in photographic films, and as intermediates in the manufacture of organic chemicals.