Alizarin

Alizarin
Names
	Preferred IUPAC name 1,2-Dihydroxyanthracene-9,10-dione
	Other names 1,2-Dihydroxy-9,10-anthracenedione; 1,2-Dihydroxyanthraquinone; Turkey red; Mordant red 11; Alizarin B; Alizarin red
Identifiers
CAS Number	72-48-0 ;
3D model (JSmol)	Interactive image;
Beilstein Reference	1914037
ChEBI	CHEBI:16866 ;
ChEMBL	ChEMBL55814 ;
ChemSpider	6056 ;
ECHA InfoCard	100.000.711
Gmelin Reference	34541
KEGG	C01474 ;
PubChem CID	6293;
UNII	60MEW57T9G ;
CompTox Dashboard (EPA)	DTXSID5045960 ;
	InChI InChI=1S/C14H8O4/c15-10-6-5-9-11(14(10)18)13(17)8-4-2-1-3-7(8)12(9)16/h1-6,15,18H Key: RGCKGOZRHPZPFP-UHFFFAOYSA-N ; InChI=1/C14H8O4/c15-10-6-5-9-11(14(10)18)13(17)8-4-2-1-3-7(8)12(9)16/h1-6,15,18H Key: RGCKGOZRHPZPFP-UHFFFAOYAG;
	SMILES O=C2c1ccccc1C(=O)c3c2ccc(O)c3O;
Properties
Chemical formula	C14H8O
Appearance	orange-red crystals or powder
Density	1.540 g/cm3
Melting point	289.5 °C (553.1 °F; 562.6 K)
Boiling point	430 °C (806 °F; 703 K)
Solubility in water	slightly to sparingly soluble
Acidity (pKa)	6.94
Hazards
	GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H302, H315, H319
Precautionary statements	P264, P270, P280, P301+P312, P302+P352, P305+P351+P338, P321, P330, P332+P313, P337+P313, P362, P501
Safety data sheet (SDS)	External MSDS
Related compounds
Related compounds	anthraquinone, anthracene
	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

Alizarin (also known as 1,2-dihydroxyanthraquinone, Mordant Red 11, C.I. 58000, and Turkey Red) is an organic compound with formula C₁₄H₈O₄ that has been used throughout history as a red dye, principally for dyeing textile fabrics. Historically it was derived from the roots of plants of the madder genus. In 1869, it became the first natural dye to be produced synthetically.

Alizarin is the main ingredient for the manufacture of the madder lake pigments known to painters as rose madder and alizarin crimson. Alizarin in the most common usage of the term has a deep red color, but the term is also part of the name for several related non-red dyes, such as Alizarine Cyanine Green and Alizarine Brilliant Blue. A use of alizarin in modern times is as a staining agent in biological research because it stains free calcium and certain calcium compounds a red or light purple color. Alizarin continues to be used commercially as a red textile dye, but to a lesser extent than in the past.