Chlorophenol red

Chlorophenol red
Names
	IUPAC name 2-Chloro-4-[3-(3-chloro-4-hydroxyphenyl)-1,1-dioxobenzo[c]oxathiol-3-yl]phenol
	Other names 3′,3′-Dichlorophenolsulfonaphthalein
Identifiers
CAS Number	4430-20-0 ;
3D model (JSmol)	Interactive image;
ChemSpider	19293 ;
ECHA InfoCard	100.022.382
EC Number	224-619-2;
PubChem CID	20486;
CompTox Dashboard (EPA)	DTXSID4063450 ;
	InChI InChI=1S/C19H12Cl2O5S/c20-14-9-11(5-7-16(14)22)19(12-6-8-17(23)15(21)10-12)13-3-1-2-4-18(13)27(24,25)26-19/h1-10,22-23H Key: WWAABJGNHFGXSJ-UHFFFAOYSA-N ; InChI=1/C19H12Cl2O5S/c20-14-9-11(5-7-16(14)22)19(12-6-8-17(23)15(21)10-12)13-3-1-2-4-18(13)27(24,25)26-19/h1-10,22-23H Key: WWAABJGNHFGXSJ-UHFFFAOYAK;
	SMILES C1=CC=C2C(=C1)C(OS2(=O)=O)(C3=CC(=C(C=C3)O)Cl)C4=CC(=C(C=C4)O)Cl;
Properties
Chemical formula	C19H12Cl2O5S
Molar mass	423.26 g·mol−1
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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	Infobox references

Chlorophenol red is an indicator dye that changes color from yellow to violet in the pH range 4.8 to 6.7. The lambda max is at 572 nm.[1]

Chlorophenol red (pH indicator)
below pH 4.8		above pH 6.7
4.8	⇌	6.7

References