2553-71-1 4,4'-(3H-2,1-Benzoxathiol-3-ylidene)bis(2-bromo-6-chlorophenol) S,S-dioxide Bromchlorophenol blue Bromochlorophenol blue EINECS 219-861-0 NSC 7816 Phenol, 4,4'-(3H-2,1-benzoxathiol-3-ylidene)bis(2-bromo-6-chloro-, S,S-dioxide (8CI)(9CI)