The dicarbon phosphide (CCP) radical was detected in IRC +10216 by
Halfen, Cloutier, and Ziurys in 2008. Five doublet pairs
of lines were identified using the
12 m telescope at the
Arizona Radio Observatory on Kitt Peak. A detailed study of the
rotatational specta of CCP, including 13C isotopomers
followed in 2009.
CCP is a cousin of CCN, which has not yet been observed.
Guélin and Cernicharo were unable to
detect it the early 1990s. Another search in IRC +10216 15 years by
Fuchs et al. also found no evidence of CCN.