Carbon monophosphide
Preferred IUPAC name
Other names
Carbon phosphide
Carbon monophosphide
Cyaphogenyl radical
3D model (JSmol)
  • InChI=1S/CP/c1-2
  • [C]#P
Molar mass 42.985 g·mol−1
Related compounds
Related compounds
CN SiP CCP radical, HCP
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Carbon monophosphide is a diatomic chemical with formula CP. It is isoelectronic with carbon monosulfide (CS) and 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.

Detection in interstellar medium

The simple diatomic carbon monophosphide (CP) was detected in the circumstellar envelope of the star IRC +10216 in 1990.[1] The identification was made by matching 10 rotational lines observed with the IRAM 30m radiotelescope.[2][3]


  1. ^ Guelin, M.; Cernicharo, J.; Paubert, G.; Turner, B. E. (1990). "Free CP in IRC +10216". Astronomy and Astrophysics. 230: L9. Bibcode:1990A&A...230L...9G.
  2. ^ "CAS 12326-85-1: Carbon monophosphide". Archived from the original on 12 July 2018. Retrieved 12 July 2018.
  3. ^ "Astromolecule of the month". Retrieved 12 July 2018.