Reactions of BrO with BrO, OBrO, and Br2O2 have been investigated using ab initio method. Calculation at Quadratic Configuration Interaction, including single and double substitutions (QCISD)(T)/6-311++G(2df)//QCISD/6-311G*+Delta ZPE level of theory suggests that BrO+BrO --> Br+OBrO be endothermic by 3.8 kcal mol(-1), and BrO + OBrO --> Br2O + O-2 be exothermic by 43.0 kcal mol(-1), agreeing well with experimental measurements. The BrO self-reaction forming BrOO + Br and BT2O2 isomers is estimated to be exothermic by 6.8-22.0 kcal mol(-1). Extractions of terminal Br from Br2O2 isomers by BrO yielding Br2O and BrO2 (i.e., BrOO or OBrO) are predicted to be exothermic by 15.1-21.0 kcal mol(-1).