Alizarin Red S

Alizarin Red S (also known as C.I. Mordant Red 3, Alizarin Carmine, and C.I 58005.^[1]) is a water-soluble sodium salt of Alizarin sulfonic acid with a chemical formula of C
₁₄H
₇NaO
₇S.^[2][1] Alizarin Red S was discovered by Graebe and Liebermann in 1871.^[2] In the field of histology alizarin Red S is used to stain calcium deposits in tissues,^[3][4] and in geology to stain and differentiate carbonate minerals.^[3]

Alizarin Red S

Names
IUPAC name 3,4-Dihydroxy-9,10-dioxo-9,10-dihydroanthracene-2-sulfonic acid
Other names Mordant Red 3 C.I 58005 Sodium alizarinesulfonate Alizarine S Alizarine sulfonate Alizarin Red, water-soluble Alizarin Carmine Alizarin sodium monosulfonate
Identifiers
CAS Number	130-22-3 Y
3D model (JSmol)	Interactive image
ChEBI	CHEBI:87358
ChemSpider	8217
ECHA InfoCard	100.004.530
EC Number	204-981-8
PubChem CID	3955344
UNII	3F3AT0Q12H Y
CompTox Dashboard (EPA)	DTXSID6052744
SMILES [Na+].Oc1c(O)c2C(=O)c3ccccc3C(=O)c2cc1S([O-])(=O)=O
Properties
Chemical formula	C14H7NaO7S
Molar mass	342.253 g/mol
Appearance	yellow-orange powder
Solubility in water	Soluble in water and ethanol
Hazards
Safety data sheet (SDS)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Uses

Alizarin Red S, as sold for use as a histologic stain.

Alizarin Red S is used in histology and histopathology to stain, or locate calcium deposits in tissues.^[1][3][4] In the presence of calcium, Alizarin Red S, binds to the calcium to form a Lake pigment that is orange to red in color.^[4] Whole specimens can be stained with Alizarin Red S to show the distribution of bone, especially in developing embryos.^[4] In living corals alizarin Red S has been used to mark daily growth layers.^[5]

In geology, Alizarin Red S is used on thin sections, and polished surfaces to help identify carbonate minerals which stain at different rates.^[6]

See also

• Aniline
• 1,2,4-Trihydroxyanthraquinone or purpurin, another red dye that occurs in madder root
• Hydroxyanthraquinone
• Dihydroxyanthraquinone
• List of dyes
• List of colors (compact)