• British Pharmacopoeia Volume V
  • Appendices
  • Appendix I A. General Reagents

Bromothymol Blue

Bromothymol Blue 4,4′-(3H-2,1-Benzoxathiol-3-ylidene)bis(2-bromothymol) S,S-dioxide; C27H28Br2O5S = 624 (76-59-5)

Produces a yellow colour in weakly acidic solutions and a blue colour in weakly alkaline solutions. Neutrality is indicated by a green colour.