Carbon monophosphide

Carbon monophosphide is a diatomic chemical with formula CP. It is a heavier analog of the cyanide radical (CN). CP and CN are both open-shell species with doublet Π ground electronic states while the ground states of CS and CO are closed-shell. The related anion, CP−, is called cyaphide and isoelectronic with CS.

Detection in interstellar medium
Carbon monophosphide was detected in the circumstellar envelope of the star IRC +10216 in 1990, observed with the IRAM 30m radiotelescope.