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Alizarin Red S

Alizarin Red S

Ionisation: Acid

Chemical structure of Alizarin Red S

Common Name: Alizarin red S
Suggested Name: Alizarin red S
Other Names:

Alizarin Alizarin carmine

C.I. Number: 58005
C.I. Name: Mordant red 3
Solubility Aqueous: 7.70%
Solubility Ethanol: 7.70%
Absorption Maximum: 557, 594-9 (Conn) 423, 546 alkaline (Gurr) 556, 596 (Aldrich)
Empirical Formula: C14H7O7SNa
Formula Weight: 342.3


Alizarin red S is sometimes used to demonstrate calcium in sections. Unlike the more commonly used method for calcium, the von Kossa, it combines with the calcium ions forming a bright red lake. It is commonly used to stain embryo skeletons in cleared whole mounts, usually of small mammals. Although sometimes simply called alizarin, it should be noted that another dye, from which it is derived by sulfonation, is more properly called by that name.


  1. R. D. Lillie.
    Conn’s Biological Stains
    Williams & Wilkins, Baltimore, MD., U.S.A.
  2. Aldrich chemical catalogue, 1992
    Aldrich Chemical Company, Milwaukee, WI, USA.
  3. Edward Gurr, 1971
    Synthetic dyes in biology, medicine and chemistry
    Academic Press, London, England.