"DDQ" redirects here. DDQ is also the former callsign of a TV station in Toowoomba, Queensland, Australia. Benzoquinone, or quinone is one of the two isomers of cyclohexadienedione. It has the molecular formula C6H4O2. Orthobenzoquinone is the 1,2-dione, whereas parabenzoquinone is the 1,4-dione. Orthobenzoquinone is the oxidized form of catechol (1,2-dihydroxybenzene), while parabenzoquinone is the oxidized form of hydroquinone. An acidic potassium iodide solution reduces a solution of benzoquinone to hydroquinone, which is oxidized back with a solution of silver nitrate. Quinone is also the name for the class of compounds containing either benzoquinone isomers as part of their structure. Quinones are not aromatic, but are dienes. The carbonyl groups are ketone-like. Image:orthobenzoquinone.svg|1,2-BenzoquinoneImage:P-Benzoquinone.png|1