Benzenediazonium tetrafluoroborate is an
organic compound
Some chemical authorities define an organic compound as a chemical compound that contains a carbon–hydrogen or carbon–carbon bond; others consider an organic compound to be any chemical compound that contains carbon. For example, carbon-co ...
with the
formula
In science, a formula is a concise way of expressing information symbolically, as in a mathematical formula or a ''chemical formula''. The informal use of the term ''formula'' in science refers to the general construct of a relationship betwe ...
6H5N2F
4. It is a salt of a
diazonium cation and
tetrafluoroborate. It exists as a colourless solid that is soluble in polar solvents. It is the parent member of the aryl
diazonium compound
Diazonium compounds or diazonium salts are a group of organic compounds sharing a common functional group where R can be any organic group, such as an alkyl or an aryl, and X is an inorganic or organic anion, such as a halide. The parent, compou ...
s, which are widely used in organic chemistry.
Synthesis
Diazotization of
aniline
Aniline (From , meaning ' indigo shrub', and ''-ine'' indicating a derived substance) is an organic compound with the formula . Consisting of a phenyl group () attached to an amino group (), aniline is the simplest aromatic amine. It is an in ...
:
: C
6H
5NH
2 + HNO
2 (from NaNO
2 and HCl) + HCl →
6H5N2l + 2 H
2O
The tetrafluoroborate can be obtained from crude benzenediazonium chloride by salt metathesis using
tetrafluoroboric acid.
:
6H5N2l + HBF
4 →
6H5N2F
4 + HCl
The tetrafluoroborate is more stable than the chloride.
Properties
The diazo group (N
2) can be replaced by many other groups, usually anions, giving a variety of substituted phenyl derivatives:
:C
6H
5N
2+ + Nu
− → C
6H
5Nu + N
2
These transformations are associated with many
named reactions including the
Schiemann reaction,
Sandmeyer reaction, and
Gomberg–Bachmann reaction. A wide range of groups that can be used to replace N
2 including halide, SH
−, CO
2H
−, OH
−. Of considerable practical value in the dye industry are the
diazo coupling reactions.
Reaction with aniline gives
1,3-diphenyltriazene.
The structure of the salt has been verified by
X-ray crystallography
X-ray crystallography is the experimental science of determining the atomic and molecular structure of a crystal, in which the crystalline structure causes a beam of incident X-rays to Diffraction, diffract in specific directions. By measuring th ...
. The N-N bond distance is 1.083(3) Å.
Safety
Whereas the chloride salt is explosive,
the tetrafluoroborate is readily isolated.
References
{{Reflist
Diazo compounds
Tetrafluoroborates
Phenyl compounds