76-59-5-Bromothymol-Blue25 Bromothymol Blue Synonym: 3′,3”-Dibromothymolsulfonphthalein, BTB CAS Number: 76-59-5 Dye Content: Min. 95% Empirical Formula (Hill Notation): C27H28Br2O5S Molecular Weight: 624.38 Physical Form: Powder Packaging: Glass Bottle