From Wikipedia, the free encyclopedia
Preferred IUPAC name
Other names
1,4-Azaphosphabutadiyne; C-Cyanophosphaethyne; Phosphinidyneacetonitrile; Cyanophosphapropyne
3D model (JSmol)
  • InChI=1S/C2NP/c3-1-2-4
  • C(#N)C#P
Molar mass 69.003 g·mol−1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Cyanophosphaethyne is an unstable molecular compound with structural formula N≡C–C≡P. It can be considered as cyanogen with one nitrogen atom replaced by phosphorus. It has been made as a dilute gas. Cyanophosphaethyne has been tentatively detected in the interstellar medium.[1] Other structural isomers, such as C≡N–C≡P (isocyanophosphapropyne), C≡C-N≡P (azaphosphadicarbon), and N≡C–P=C (isocyanophosphavinylidene), have not been observed.[2] The molecule has linear molecular geometry (C∞v molecular symmetry).[3]


Cyanophosphaethyne can be produced by heating cyanogen azide and phosphaethyne gases to 700 °C:[4]

N≡C–N3 + H–C≡P → N≡C–C≡P + HN3

Another method is to heat anhydrous methyl cyanide with anhydrous phosphorus trichloride:[5]

N≡C–CH3 + PCl3 → N≡C–C≡P + 3HCl


The dipole moment is 3.5 Debye.[4] Having a large dipole makes the molecule easier to detect by certain types of spectroscopy than many other phosphorus containing molecules.[4] The bond lengths are C≡N = 1.159 Å, C–C = 1.378 Å, and C≡P = 1.544 Å.[4]


  1. ^ Agúndez, Marcelino; Cernicharo, José; Guélin, Michel (15 October 2014). "New molecules in IRC +10216: confirmation of C5S and tentative identification of MgCCH, NCCP, and SiH3CN". Astronomy & Astrophysics. 570: A45. arXiv:1408.6306. Bibcode:2014A&A...570A..45A. doi:10.1051/0004-6361/201424542.
  2. ^ Pham-Tran, Nguyen-Nguyen; Hajgató, Balázs; Veszpre´mi, Tamás; Tho Nguyen, Minh (2001). "Theoretical study of cyanophosphapropyne (NCCP), isocyanophosphapropyne (CNCP) and their isomers: stability and properties". Physical Chemistry Chemical Physics. 3 (9): 1588–1597. Bibcode:2001PCCP....3.1588P. doi:10.1039/b100463h.
  3. ^ Kwon, Ohyun; McKee, Michael L. (January 2001). "Theoretical Calculations on the NCCP Potential Energy Surface". The Journal of Physical Chemistry A. 105 (2): 478–483. Bibcode:2001JPCA..105..478K. doi:10.1021/jp0031855.
  4. ^ a b c d Cooper, Terry A.; Kroto, Harold W.; Nixon, John F.; Ohashi, Osamu (1980). "Detection of C-cyanophosphaethyne, N≡C–C≡P, by microwave spectroscopy". J. Chem. Soc., Chem. Commun. (8): 333–334. doi:10.1039/C39800000333.
  5. ^ Bizzocchi, Luca; Thorwirth, Sven; Müller, Holger S.P.; Lewen, Frank; Winnewisser, Gisbert (January 2001). "Submillimeter-Wave Spectroscopy of Phosphaalkynes: HCCCP, NCCP, HCP, and DCP". Journal of Molecular Spectroscopy. 205 (1): 110–116. Bibcode:2001JMoSp.205..110B. doi:10.1006/jmsp.2000.8234. PMID 11148114.