Cresol Red

Cresol Red
Names
	Preferred IUPAC name 3,3-Bis(4-hydroxy-3-methylphenyl)-2,1λ6-benzoxathiole-1,1(3H)-dione
Identifiers
CAS Number	1733-12-6 ;
3D model (JSmol)	Interactive image;
ChEBI	CHEBI:86218 ;
ChemSpider	65818 ;
ECHA InfoCard	100.015.513
PubChem CID	73013;
UNII	839K2R4B8K ;
CompTox Dashboard (EPA)	DTXSID8061929 ;
	InChI InChI=1S/C21H18O5S/c1-13-11-15(7-9-18(13)22)21(16-8-10-19(23)14(2)12-16)17-5-3-4-6-20(17)27(24,25)26-21/h3-12,22-23H,1-2H3 Key: OBRMNDMBJQTZHV-UHFFFAOYSA-N ; InChI=1/C21H18O5S/c1-13-11-15(7-9-18(13)22)21(16-8-10-19(23)14(2)12-16)17-5-3-4-6-20(17)27(24,25)26-21/h3-12,22-23H,1-2H3 Key: OBRMNDMBJQTZHV-UHFFFAOYAD;
	SMILES Cc1cc(ccc1O)/C(=C/2C=CC(=O)C(=C2)C)c3ccccc3OS(O)=O;
Properties
Chemical formula	C21H17NaO5S
Molar mass	382.43 g/mol
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) Infobox references

Cresol red (full name: o-cresolsulfonephthalein)^[1] is a triarylmethane dye frequently used for monitoring the pH in aquaria.