Dibromine trioxide is the chemical compound composed of bromine and oxygen with the formula Br2O3.

It has the structure Br−O−BrO2 (bromine bromate).

[4] Dibromine trioxide can be prepared by reacting a solution of bromine in dichloromethane with ozone at low temperatures.

[3][5] It disproportionates in alkali solutions to Br− and BrO−3.

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