This prefix is now rejected. It has been used in the past, especially in cyclic systems,
to name
carbenes, e.g. '
carbenacycloheptane', now cycloheptylidene.
Source:
PAC, 1995, 67, 1307
(Glossary of class names of organic compounds and reactivity intermediates based on
structure (IUPAC Recommendations 1995))
on page 1324