semiquinone

[ sem-ee-kwi-nohn, -kwin-ohn, sem-ahy- ]
/ ˌsɛm i kwɪˈnoʊn, -ˈkwɪn oʊn, ˌsɛm aɪ- /

noun Chemistry.

any of the class of free radicals formed as intermediates in the oxidation of a hydroquinone to a quinone.

Origin of semiquinone