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",[1] though derivatives are known.
An alkylated p-benzoquinone has been found in the rhizomes of Iris kemaonensis.[2]