c7h7no3


From The Collaborative International Dictionary of English v.0.48:

Orcein \Or"ce*in\, n. (Chem.)
   A reddish brown amorphous dyestuff, C7H7NO3, obtained from
   orcin, and forming the essential coloring matter of cudbear
   and archil. It is closely related to litmus.
   [1913 Webster]
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