quinone (redirected from quinoid)

quinone

Any member of a class of cyclic organic compounds comprising a six-membered unsaturated ring (see saturation) to which two oxygen atoms are bonded as carbonyl groups (−C=O; see functional group). This structure plays an important role in theories of chemical structure and colour, since quinones occur as pigments in bacteria, fungi, and certain higher plants; animals containing quinones obtain them from plants they eat. The K vitamins (see vitamin K) are naphthoquinones. The term quinone often specifically denotes para-benzoquinone (C₆H₄O₂), a bright yellow solid with a sharp odour used in manufacturing dyes and fungicides and in photography.

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quinone [′kwi‚nōn]

(organic chemistry)

CO(CHCH)₂CO Yellow crystalline compound with irritating aroma; melts at 116°C; soluble in alcohol, alkalies, and ether; used to make dyes and hydroquinone. Also known as benzoquinone; chinone.