Bromine dioxide is the chemical compound composed of bromine and oxygen with the formula BrO2. It forms unstable yellow to yellow-orange crystals. It was first isolated by R. Schwarz and M. Schmeißer in 1937 and is hypothesized to be important in the atmospheric reaction of bromine with ozone.[1] It is similar to chlorine dioxide, the dioxide of its halogen neighbor one period higher on the periodic table.
__TOC__
Bromine dioxide is formed when an electric current is passed through a mixture of bromine and oxygen gases at low temperature and pressure.
Bromine dioxide can also be formed by the treatment of bromine gas with ozone in trichlorofluoromethane at −50 °C.
When mixed with a base, bromine dioxide gives the bromide and bromate anions:
6 BrO2 + 6 NaOH → NaBr + 5 NaBrO3 + 3 H2O