benzoquinone
Benzoquinone (C6H4O2) is a quinone with a single benzene ring. There are 2 (out of 3 hypothetical) benzoquinones:
- 1,4-Benzoquinone, most commonly, right image (also para-benzoquinone, p-benzoquinone, para-quinone, or just quinone)
- 1,2-Benzoquinone, less commonly, left image (also ortho-benzoquinone, o-benzoquinone, ortho-quinone)
- 1,3-benzoquinone "does not exist, because its structure would be nonplanar and highly strained",{{Cite thesis|doi=10.6100/IR535691 |title=Pulsed corona-induced degradation of organic materials in water.|year=2000 |last1=Hoeben |first1=WFLM Wilfred|publisher=Technische Universiteit Eindhoven}} though derivatives are known.
An alkylated p-benzoquinone has been found in the rhizomes of Iris kemaonensis.{{cite journal |last1=Singh |first1=N. |last2=Mahmood |first2=U. |last3=Kaul |first3=V. K. |last4=Gupta |first4=A. P. |last5=Jirovetz |first5=L. |year=2006 |title=A new alkylated benzoquinone from rhizomes of Iris kumaonensis |pmid=16286313 |journal=Nat. Prod. Res. |volume=20 |issue=1 |pages=75–78 |doi= 10.1080/14786410500045721|s2cid=38713868 }}