Methylidynephosphane chemical structure
Space filling model
Preferred IUPAC name
Other names
Hydrogen cyaphide[citation needed]
  • 6829-52-3
3D model (JSmol)
  • Interactive image
  • 122445
  • 138843
  • DTXSID80218444 Edit this at Wikidata
  • InChI=1S/CHP/c1-2/h1H
  • C#P
Molar mass 43.993 g·mol−1
Conjugate base Cyaphide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Methylidynephosphane (phosphaethyne) is a chemical compound which was the first phosphaalkyne compound discovered, containing the unusual C≡P carbon-phosphorus triple bond.


Methylidynephosphane is the phosphorus analogue of hydrogen cyanide, with the nitrile nitrogen replaced by phosphorus. Methylidynephosphane can be synthesised via the reaction of phosphine with carbon,[1] but it is extremely reactive and polymerises readily at temperatures above −120 °C. However, several types of derivatives, with bulky groups, such as tert-butyl or trimethylsilyl, substituted for the hydrogen atom, are much more stable, and are useful reagents for the synthesis of various organophosphorus compounds.[2] The PCO and PCS anions are also known.[3]


While the existence of the molecule had been discussed,[4] and early attempts had been made to prepare it, methylidynephosphane was first successfully synthesised in 1961, by T.E. Gier of E. I. duPont de Nemours, Inc.[1][5] Earlier reports of preparing its sodium salt were reported as unreproducible by this author. Methylidynephosphane may have contributed to an explosion that killed Vera Bogdanovskaia, an early chemist pursuing it, one of the first female chemists in Russia,[6] and perhaps the first to die as a result of her own research.[7][8]


  1. ^ a b Gier TE (1961). "HCP, A Unique Phosphorus Compound". J. Am. Chem. Soc. 83 (7): 1769–1770. doi:10.1021/ja01468a058.
  2. ^ Regitz M (1990). "Phosphaalkynes: new building blocks in synthetic chemistry". Chem. Rev. 90: 191–213. doi:10.1021/cr00099a007.
  3. ^ Hubler K, Schwerdtfeger P. (1999). "Theoretical Studies of NMR Chemical Shifts and Vibrational Frequencies in λ3-Phosphaalkynes P≡C-R". Inorg. Chem. 38: 157–164. doi:10.1021/ic9811291.
  4. ^ H. Albers (1950) Angew. Chemie 62:443-467
  5. ^ Philip P. Power (1999) π-Bonding and the Lone Pair Effect in Multiple Bonds between Heavier Main Group Elements, Chem. Rev. 99(12):3463-3503, esp. 3491, see [1] Archived 2016-10-20 at the Wayback Machine, accessed 2 July 2014.
  6. ^ Ledkovskaia-Astman, Marina; Rosenthal, Charlotte; Zirin, Mary Fleming (1994). Dictionary of Russian Women Writers. Westport, CT: Greenwood Publishing Group. ISBN 978-0-313-26265-4.
  7. ^ Rayner-Canham, Marelene; Rayner-Canham, Geoffrey (2001). Women in Chemistry: Their Changing Roles from Alchemical Times to the Mid-twentieth Century. Philadelphia: Chemical Heritage Foundation. p. 64. ISBN 978-0-941901-27-7.
  8. ^ Ogilvie, Marilyn; Harvey, Joy (16 December 2003). Biographical Dictionary of Women in Science. p. 311. ISBN 1135963436.