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Rhodamine B

Rhodamine B

Class: Rhodamine
Ionisation: Basic

Chemical structure of Rhodamine B

Common Name: Rhodamine B
Suggested Name: Rhodamine B
Other Names:

C.I. Number: 45170
C.I. Name: Basic violet 10
Color: Red
Solubility Aqueous: Very
Solubility Ethanol: Very
Absorption Maximum: 556.5 (Conn), 548 (Gurr) 543, 355 (Aldrich)
Empirical Formula: C28H31N2O3Cl
Formula Weight: 479


Rhodamine B is an amphoteric dye, although usually listed as basic as it has an overall positive charge. It is most commonly used as a fluorochrome, an example being in mixture with auramine O to demonstrate acid fast organisms.

The structural formula given in the Merck Index is slightly different than in Conn, having methyl groups instead of ethyl groups.


  1. R. D. Lillie.
    Conn’s Biological Stains
    Williams & Wilkins, Baltimore, MD., U.S.A.
  2. Edward Gurr, 1971
    Synthetic dyes in biology, medicine and chemistry
    Academic Press, London, England.
  3. Aldrich chemical catalogue, 1992
    Aldrich Chemical Company, Milwaukee, WI, USA.
  4. Susan Budavari, Editor,
    The Merck Index, Ed. 12
    Merck & Co., Inc., Whitehouse Station, NJ, USA