Methylidynephosphane (phosphaethyne) is a chemical compound which was the first
phosphaalkyne compound discovered, containing the unusual
C≡P carbon
Carbon () is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalent—its atom making four electrons available to form covalent chemical bonds. It belongs to group 14 of the periodic table. Carbon ma ...
-
phosphorus
Phosphorus is a chemical element with the symbol P and atomic number 15. Elemental phosphorus exists in two major forms, white phosphorus and red phosphorus, but because it is highly reactive, phosphorus is never found as a free element on Ea ...
triple bond
A triple bond in chemistry is a chemical bond between two atoms involving six bonding electrons instead of the usual two in a covalent single bond. Triple bonds are stronger than the equivalent single bonds or double bonds, with a bond order o ...
.
Description
Methylidynephosphane is the phosphorus analogue of
hydrogen cyanide
Hydrogen cyanide, sometimes called prussic acid, is a chemical compound with the formula HCN and structure . It is a colorless, extremely poisonous, and flammable liquid that boils slightly above room temperature, at . HCN is produced on a ...
, with the
nitrile
In organic chemistry, a nitrile is any organic compound that has a functional group. The prefix '' cyano-'' is used interchangeably with the term ''nitrile'' in industrial literature. Nitriles are found in many useful compounds, including me ...
nitrogen replaced by phosphorus. Methylidynephosphane can be synthesised via the reaction of
phosphine
Phosphine (IUPAC name: phosphane) is a colorless, flammable, highly toxic compound with the chemical formula , classed as a pnictogen hydride. Pure phosphine is odorless, but technical grade samples have a highly unpleasant odor like rotting ...
with carbon,
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
A trimethylsilyl group (abbreviated TMS) is a functional group in organic chemistry. This group consists of three methyl groups bonded to a silicon atom minus;Si(CH3)3 which is in turn bonded to the rest of a molecule. This structural group is ch ...
, substituted for the hydrogen atom, are much more stable, and are useful reagents for the synthesis of various organophosphorus compounds. The PCO
− and PCS
− anion
An ion () is an atom or molecule with a net electrical charge.
The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by conve ...
s are also known.
History
While the existence of the molecule had been discussed, 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.[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, se]
, accessed 2 July 2014. 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,
and perhaps the first to die as a result of her own research.
References
{{Molecules detected in outer space
Organophosphanes