Methylidynephosphane (phosphaethyne) is a chemical compound with the
chemical formula
A chemical formula is a way of presenting information about the chemical proportions of atoms that constitute a particular chemical compound or molecule, using chemical element symbols, numbers, and sometimes also other symbols, such as pare ...
. It was the first
phosphaalkyne compound discovered, containing the unusual
C≡P carbon
Carbon () is a chemical element; it has chemical symbol, symbol C and atomic number 6. It is nonmetallic and tetravalence, tetravalent—meaning that its atoms are able to form up to four covalent bonds due to its valence shell exhibiting 4 ...
-
phosphorus
Phosphorus is a chemical element; it has Chemical symbol, symbol P and atomic number 15. All elemental forms of phosphorus are highly Reactivity (chemistry), reactive and are therefore never found in nature. They can nevertheless be prepared ar ...
triple bond
A triple bond in chemistry is a chemical bond between two atoms involving six Electron pair bond, bonding electrons instead of the usual two in a covalent bond, covalent single bond. Triple bonds are stronger than the equivalent covalent bond, sin ...
. Although isolated samples of methylidynephosphane are impractical, other derivatives have been well studied such as
''tert''-butylphosphaacetylene. The conjugate base of methylidynephosphane is
cyaphide.
Description
Methylidynephosphane is the phosphorus analogue of
hydrogen cyanide
Hydrogen cyanide (formerly known as prussic acid) is a chemical compound with the chemical formula, formula HCN and structural formula . It is a highly toxic and flammable liquid that boiling, boils slightly above room temperature, at . HCN is ...
, with the
nitrile
In organic chemistry, a nitrile is any organic compound that has a functional group. The name of the compound is composed of a base, which includes the carbon of the , suffixed with "nitrile", so for example is called " propionitrile" (or pr ...
nitrogen replaced by phosphorus. Methylidynephosphane can be synthesized 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 i ...
, substituted for the hydrogen atom, are much more stable, and are useful reagents for the synthesis of various
organophosphorus compound
Organophosphorus chemistry is the scientific study of the synthesis and properties of organophosphorus compounds, which are organic compounds containing phosphorus. They are used primarily in pest control as an alternative to chlorinated hydrocarbo ...
s. The (cyaphate) and (thiocyaphate)
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 conven ...
s are also known.
HCP has been detected in the
interstellar medium
The interstellar medium (ISM) is the matter and radiation that exists in the outer space, space between the star systems in a galaxy. This matter includes gas in ionic, atomic, and molecular form, as well as cosmic dust, dust and cosmic rays. It f ...
.
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 Gier. 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 woman to die from her own research.
References
{{Molecules detected in outer space
Organophosphanes