Bromine(III) fluorosulfonate is an inorganic compound of bromine, sulfur, fluorine, and oxygen with the chemical formula . This is a trivalent compound of bromine from the group of fluorosulfonates.
The compound is formed as a reaction product of bromine and peroxydisulfuryl difluoride:
Bromine(III) fluorosulfonate is very hygroscopic and reacts exothermically with water:
The monovalent bromine(I) fluorosulfonate can be formed by adding bromine to bromine(III) fluorosulfonate: