Methylidenecyclohexadienones and dimethylidenecyclohexadienes, formally derived from
quinones by replacement of one or both of the quinone oxygens by methylidene groups. (The
diradical,
triplet state of quinodimethanes can also be called
o- or
p-xylylenes).
Source:
PAC, 1995, 67, 1307
(Glossary of class names of organic compounds and reactivity intermediates based on
structure (IUPAC Recommendations 1995))
on page 1362