C6H4O2

from The Collaborative International Dictionary of English v.0.48
Quinone \Qui"none\, n. [Quinine + ketone.] (Chem.)
   A crystalline substance, {C6H4O2} (called also
   {benzoketone}), first obtained by the oxidation of quinic
   acid and regarded as a double ketone; also, by extension, any
   one of the series of which quinone proper is the type.
   [Written also {chinone}, {kinone}.]
   [1913 Webster]
    

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