The
diradicalCH2=C(C.H2)2, 2-methylenepropane-1,3-diyl, for which no Kekulé structure can be written, and its
hydrocarbyl derivatives.
Source:
PAC, 1995, 67, 1307
(Glossary of class names of organic compounds and reactivity intermediates based on
structure (IUPAC Recommendations 1995))
on page 1373