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Names | |||
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IUPAC name
Nitrate radical
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Systematic IUPAC name
Trioxidonitrogen(•) | |||
Identifiers | |||
3D model (
JSmol)
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ChEBI | |||
ChemSpider | |||
1573 | |||
PubChem
CID
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Properties | |||
NO3 | |||
Molar mass | 62.004 g·mol−1 | ||
Except where otherwise noted, data are given for materials in their
standard state (at 25 °C [77 °F], 100 kPa).
|
Nitrogen trioxide or nitrate radical is an
oxide of
nitrogen with formula NO
3, consisting of three
oxygen atoms
covalently bound to a nitrogen atom. This highly unstable blue compound has not been isolated in pure form, but can be generated and observed as a short-lived component of gas, liquid, or solid systems.
[1]
Like
nitrogen dioxide NO
2, it is a
radical (a molecule with an unpaired
valence electron), which makes it
paramagnetic. It is the uncharged counterpart of the
nitrate
anion NO−
3 and an
isomer of the
peroxynitrite radical OONO.
[1]
Nitrogen trioxide is an important intermediate in reactions between atmospheric components, including the destruction of ozone. [1] [2]
The existence of the NO
3 radical was postulated in 1881-1882 by Hautefeuille and Chappuis to explain the absorption spectrum of air subjected to a silent electrical discharge.
[1]
The neutral NO
3 molecule appears to be planar, with three-fold rotational symmetry (symmetry group D3h); or possibly a
resonance between three Y-shaped molecules.
[1]
The NO
3 radical does not react directly with water, and is relatively unreactive towards closed-shell molecules, as opposed to isolated atoms and other radicals. It is decomposed by light of certain wavelengths into
nitric oxide NO and oxygen O
2.
[1]
The absorption spectrum of NO
3 has a broad band for light with
wavelengths from about 500 to 680
nm, with three salient peaks in the
visible at 590, 662, and 623 nm. Absorption in the range 640–680 nm does not lead to dissociation but to
fluorescence: specifically, from about 605 to 800 nm following excitation at 604.4 nm, and from about 662 to 800 nm following excitation at 661.8 nm.
[1] In water solution, another absorption band appears at about 330 nm (
ultraviolet). An excited state NO*
3 can be achieved by photons of wavelength less than 595 nm.
[1]
Nitrogen trioxide can be prepared in the gas phase by mixing nitrogen dioxide and ozone: [1]
This reaction can be performed also in the solid phase or water solutions, by irradiating frozen gas mixtures, flash photolysis and radiolysis of nitrate salts and nitric acid, and several other methods. [1]
Nitrogen trioxide is a product of the
photolysis of
dinitrogen pentoxide N
2O
5,
chlorine nitrate ClONO
2, and
peroxynitric acid HO
2NO
2 and its salts.
[1]