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Azure C

Azure C

Class: Thiazin
Ionisation: Basic

Chemical structure of Azure C

Common Name: Azure C
Suggested Name: Azure C
Other Names:

Methylene azure C

C.I. Number: 52002
C.I. Name:
Color: Blue
Solubility Aqueous: Readily
Solubility Ethanol: Readily
Absorption Maximum: 616 (Aldrich) 607-610 (Conn) 608-622 (Merck)
Empirical Formula: C13H12N3SCl
Formula Weight: 277.8


Azure C is formed by the oxidation of Methylene blue and is strongly metachromatic. Compare the formula of the three azures and methylene blue.


  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. Susan Budavari, Editor,
    The Merck Index, Ed. 12
    Merck & Co., Inc., Whitehouse Station, NJ, USA
  4. Edward Gurr, 1971
    Synthetic dyes in biology, medicine and chemistry
    Academic Press, London, England.