The cyclic C3H radical (c-C3H) was observed first in the
laboratory and then toward
Nobeyama Radio Observatory by
Yamamoto et al. in
Mangum & Wootten observed c-C3H
in 13 additional sources. A theoretical study by
Ochsenfeld et al. concluded that c-C3H could be
formed efficiently in the interstellar medium through the reaction of carbon atoms with acetylene.
c-C3H is a radical of
cyclopropenylidene and is therefore also a
carbene, where the bridging carbon only forms
two single bonds with the other two carbons.