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Pyronin B

Pyronin B

Class: Pyronin
Ionisation: Basic

Chemical structure of Pyronin B
Chemical structure of Pyronin B

Common Name: Pyronin B
Suggested Name: Pyronin B
Other Names:

C.I. Number: 45010
C.I. Name:
Color: Red
Solubility Aqueous: Very
Solubility Ethanol: Very
Absorption Maximum: 550 (Gurr) 553 (Aldrich) 555 (Conn)
Empirical Formula: C21H27N2OCl
Formula Weight: 359 (Conn)1042.3 (Aldrich)


The formula on the top is from Conn. The one on the bottom is from Green, and illustrates the suggestion that two molecules of pyronin B are linked through ferric chloride into a larger molecule due to oxidation with ferric chloride during manufacture. This explains the difference in formula weights.

Pyronin B is sometimes substituted for pyronin Y in the Unna-Pappenheim stain for nucleic acids, but is not generally considered to be as effective for that purpose.

Compare the formula with other pyronins.


  1. R. D. Lillie.
    Conn’s Biological Stains
    Williams & Wilkins, Baltimore, MD., U.S.A.
  2. Susan Budavari, Editor,
    The Merck Index, Ed. 12
    Merck & Co., Inc., Whitehouse Station, NJ, USA
  3. Green, F (1990)
    The Sigma-Aldrich handbook of stains, dyes and indicators
    Aldrich Chemical Company, Milwaukee, Wisconsin, USA
  4. Edward Gurr, 1971
    Synthetic dyes in biology, medicine and chemistry
    Academic Press, London, England.