Tetracyanomethane or carbon tetracyanide is a
percyanoalkane molecular
carbon nitride with formula C(CN)
4. The structure can be considered as
methane
Methane ( , ) is a chemical compound with the chemical formula (one carbon atom bonded to four hydrogen atoms). It is a group-14 hydride, the simplest alkane, and the main constituent of natural gas. The relative abundance of methane on Ear ...
with all hydrogen atoms replaced by
cyanide
Cyanide is a naturally occurring, rapidly acting, toxic chemical that can exist in many different forms.
In chemistry, a cyanide () is a chemical compound that contains a functional group. This group, known as the cyano group, consists of ...
groups. It was first made by
Erwin Mayer Erwin may refer to:
People Given name
* Erwin Chargaff (1905–2002), Austrian biochemist
* Erwin Dold (1919–2012), German concentration camp commandant in World War 2
* Erwin Hauer (1926–2017), Austrian-born American sculptor
* Egon Erwin Kisc ...
in 1969.
Properties
Tetracyanomethane is a solid at room temperature. It decomposes over 160 °C without melting, and although it can be in a dilute vapour, no liquid form is known.
[
The molecules of tetracyanomethane have a ]tetrahedral
In geometry, a tetrahedron (plural: tetrahedra or tetrahedrons), also known as a triangular pyramid, is a polyhedron composed of four triangular faces, six straight edges, and four vertex corners. The tetrahedron is the simplest of all the ...
symmetry (3''m'' or Td). The molecule has C-C distance of 1.484 Å and C-N distance of 1.161 Å in the gas form. In the solid the C≡N bond shortens to 1.147 Å.[ The C-C bond has a force constant of 4.86×105 dyn/cm which is slightly greater than the C-Cl bond in ]carbon tetrachloride
Carbon tetrachloride, also known by many other names (such as tetrachloromethane, also recognised by the IUPAC, carbon tet in the cleaning industry, Halon-104 in firefighting, and Refrigerant-10 in HVACR) is an organic compound with the chemi ...
, but a fair bit weaker than in the tricyanomethanide
Cyanoform (tricyanomethane) is a cyanocarbon and derivative of methane with three cyano groups. For many years, chemists have been unable to isolate this compound as a neat, free acid. However, in September 2015, reports surfaced of a successfu ...
ion.[ At pressures over 7 GPa tetracyanomethane starts to polymerize to form a disorganised covalent network solid. At higher pressure the colour yellows and darkens to black. Over 20 GPa the polymerization is total.][
]
Production
Tetracyanomethane can be made by reacting cyanogen chloride
Cyanogen chloride is a highly toxic chemical compound with the formula CNCl. This linear, triatomic pseudohalogen is an easily condensed colorless gas. More commonly encountered in the laboratory is the related compound cyanogen bromide, a room-t ...
with silver tricyanomethanide.
Reactions
In an acid solution in water tetracyanomethane is hydrolysed to yield tricyanomethanide
Cyanoform (tricyanomethane) is a cyanocarbon and derivative of methane with three cyano groups. For many years, chemists have been unable to isolate this compound as a neat, free acid. However, in September 2015, reports surfaced of a successfu ...
and ammonium ions along with carbon dioxide. In alkaline solutions tricyanomethanide and cyanate
Cyanate is an anion with the structural formula , usually written . It also refers to any salt containing it, such as ammonium cyanate.
It is an isomer of the much less stable fulminate anion .William R. Martin and David W. Ball (2019): "Sm ...
ions are produced.[
]
See also
*Tricyanomethane
Cyanoform (tricyanomethane) is a cyanocarbon and derivative of methane with three cyano groups. For many years, chemists have been unable to isolate this compound as a neat, free acid. However, in September 2015, reports surfaced of a successfu ...
(cyanoform)
References
{{Cyanides, state=collapsed
Nitriles