10018.12 a-Hexabromocyclododecane (a-HBCDD) [134237-50-6] 11149.12 ß-Hexabromocyclododecane (ß-HBCDD) [134237-51-7] 11150.12 ?-Hexabromocyclododecane (?-HBCDD) [134237-52-8]