Cresol purple

Jump to navigation Jump to search


A purplish crystalline powder used as an acid-base indicator. Cresol purple changes from red to yellow over a pH range of 1.2 -1.8 and changes again from yellow to purple from pH 7.4 - 9.0.

Chemical structure

Cresol purple.jpg

Synonyms and Related Terms

meta-cresolsulfonphthalein; m-cresol purple; púrpura de m-cresol (Esp.); porpora cresolo (It.)


  • Inhalation, ingestion and contact may cause irritation and redness.
  • ThermoFisher: SDS

Physical and Chemical Properties

Soluble in ethanol, water, dilute acid and dilute alkalis.

Composition C21H18O5S
CAS 2303-01-7
Molecular Weight mol. wt. = 382.44

Resources and Citations

  • Richard S. Lewis, Hawley's Condensed Chemical Dictionary, Van Nostrand Reinhold, New York, 10th ed., 1993
  • G.S.Brady, Materials Handbook, McGraw-Hill Book Co., New York, 1971
  • Sigma Dyes, Stains and Natural Pigments, Infrared Library, Nicolet, 1991-1995 Comment: OMNIC: formula= C21H18O5S, CAS= 2303-01-7

Retrieved from ""