Congo red

Congo red
Names
	IUPAC name disodium 4-amino-3-[4-[4-(1-amino-4-sulfonato-naphthalen-2-yl)diazenylphenyl]phenyl]diazenyl-naphthalene-1-sulfonate
Identifiers
CAS Number	573-58-0 ;
3D model (JSmol)	Interactive image;
ChEMBL	ChEMBL429694 ;
ChemSpider	10838 ;
ECHA InfoCard	100.008.509
MeSH	Congo+red
PubChem CID	11313;
UNII	3U05FHG59S ;
CompTox Dashboard (EPA)	DTXSID4022816 ;
	InChI InChI=1S/C32H24N6O6S2.2Na/c33-31-25-7-3-1-5-23(25)29(45(39,40)41)17-27(31)37-35-21-13-9-19(10-14-21)20-11-15-22(16-12-20)36-38-28-18-30(46(42,43)44)24-6-2-4-8-26(24)32(28)34;;/h1-18H,33-34H2,(H,39,40,41)(H,42,43,44);;/q;2+1/p-2/b37-35+,38-36+;; Key: IQFVPQOLBLOTPF-HKXUKFGYSA-L ; InChI=1/C32H24N6O6S2.2Na/c33-31-25-7-3-1-5-23(25)29(45(39,40)41)17-27(31)37-35-21-13-9-19(10-14-21)20-11-15-22(16-12-20)36-38-28-18-30(46(42,43)44)24-6-2-4-8-26(24)32(28)34;;/h1-18H,33-34H2,(H,39,40,41)(H,42,43,44);;/q;2+1/p-2/b37-35+,38-36+;; Key: IQFVPQOLBLOTPF-COCKEIKOBB;
	SMILES [Na+].[Na+].[O-]S(=O)(=O)c5cc(/N=N/c1ccc(cc1)c4ccc(/N=N/c3cc(c2ccccc2c3N)S([O-])(=O)=O)cc4)c(N)c6c5cccc6;
Properties
Chemical formula	C32H22N6Na2O6S2
Molar mass	696.665
	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

Congo red is an organic compound, the sodium salt of 3,3′-([1,1′-biphenyl]-4,4′-diyl)bis(4-aminonaphthalene-1-sulfonic acid). It is an azo dye. Congo red is water-soluble, yielding a red colloidal solution; its solubility is greater in organic solvents. The use of Congo red in the textile industry has long been abandoned, primarily because of its carcinogenic properties,^[1] but it is still used for histological staining.

^ Klaus Hunger, Peter Mischke, Wolfgang Rieper, Roderich Raue, Klaus Kunde, Aloys Engel: "Azo Dyes" in Ullmann's Encyclopedia of Industrial Chemistry, 2005, Wiley-VCH, Weinheim.doi:10.1002/14356007.a03_245.

[Azodye-1] Klaus Hunger, Peter Mischke, Wolfgang Rieper, Roderich Raue, Klaus Kunde, Aloys Engel: "Azo Dyes" in Ullmann's Encyclopedia of Industrial Chemistry, 2005, Wiley-VCH, Weinheim.doi:10.1002/14356007.a03_245.

[1]