Benzene rings which contain two ketone moieties in any position. They can be substituted in any position except at the ketone groups.

Synonyms: 0, o-Benzoquinones, 2,5-Cyclohexadiene-1,4-Diones, 1,2-Benzoquinones, Benzodiones, Benzoquinones, 1,4-Benzoquinones, p-Benzoquinones