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Dinitrogen pentoxide is the
chemical compound A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) containing atoms from more than one chemical element held together by chemical bonds. A molecule consisting of atoms of only one element ...
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 ...
, also known as nitrogen pentoxide or nitric anhydride. It is one of the binary
nitrogen oxide Nitrogen oxide may refer to a binary compound of oxygen and nitrogen, or a mixture of such compounds: Charge-neutral *Nitric oxide (NO), nitrogen(II) oxide, or nitrogen monoxide * Nitrogen dioxide (), nitrogen(IV) oxide * Nitrogen trioxide (), or ...
s, a family of compounds that only contain
nitrogen Nitrogen is the chemical element with the symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at se ...
and
oxygen Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements ...
. It exists as colourless crystals that melt at 41 °C. Its boiling point is 47 °C, and sublimes slightly above room temperature, yielding a colorless gas.Peter Steele Connell
The Photochemistry of Dinitrogen Pentoxide
'. Ph. D. thesis, Lawrence Berkeley National Laboratory.
Dinitrogen pentoxide is an unstable and potentially dangerous oxidizer that once was used as a
reagent In chemistry, a reagent ( ) or analytical reagent is a substance or compound added to a system to cause a chemical reaction, or test if one occurs. The terms ''reactant'' and ''reagent'' are often used interchangeably, but reactant specifies a ...
when dissolved in
chloroform Chloroform, or trichloromethane, is an organic compound with formula C H Cl3 and a common organic solvent. It is a colorless, strong-smelling, dense liquid produced on a large scale as a precursor to PTFE. It is also a precursor to various ...
for
nitration In organic chemistry, nitration is a general class of chemical processes for the introduction of a nitro group into an organic compound. The term also is applied incorrectly to the different process of forming nitrate esters between alcohols an ...
s but has largely been superseded by nitronium tetrafluoroborate (). is a rare example of a compound that adopts two structures depending on the conditions. The solid is a salt, nitronium nitrate, consisting of separate nitronium cations and nitrate anions ; but in the gas phase and under some other conditions it is a covalently-bound molecule.W. Rogie Angus, Richard W. Jones, and Glyn O. Phillips (1949): "Existence of Nitrosyl Ions (NO+) in Dinitrogen Tetroxide and of Nitronium Ions () in Liquid Dinitrogen Pentoxide". ''Nature'', volume 164, pages 433–434.


History

was first reported by Deville in 1840, who prepared it by treating
silver nitrate Silver nitrate is an inorganic compound with chemical formula . It is a versatile precursor to many other silver compounds, such as those used in photography. It is far less sensitive to light than the halides. It was once called ''lunar causti ...
() with
chlorine Chlorine is a chemical element with the symbol Cl and atomic number 17. The second-lightest of the halogens, it appears between fluorine and bromine in the periodic table and its properties are mostly intermediate between them. Chlorine i ...
.


Structure and physical properties

Pure solid is a
salt Salt is a mineral composed primarily of sodium chloride (NaCl), a chemical compound belonging to the larger class of salts; salt in the form of a natural crystalline mineral is known as rock salt or halite. Salt is present in vast quant ...
, consisting of separated linear
nitronium ion The nitronium ion, , is a cation. It is an onium ion because its nitrogen atom has +1 charge, similar to ammonium ion . It is created by the removal of an electron from the paramagnetic nitrogen dioxide molecule , or the protonation of nitric ...
s and planar trigonal
nitrate Nitrate is a polyatomic ion with the chemical formula . Salts containing this ion are called nitrates. Nitrates are common components of fertilizers and explosives. Almost all inorganic nitrates are soluble in water. An example of an insolu ...
anions . Both
nitrogen Nitrogen is the chemical element with the symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at se ...
centers have
oxidation state In chemistry, the oxidation state, or oxidation number, is the hypothetical charge of an atom if all of its bonds to different atoms were fully ionic. It describes the degree of oxidation (loss of electrons) of an atom in a chemical compound. C ...
+5. It crystallizes in the space group ''D'' (''C''6/''mmc'') with ''Z'' = 2, with the anions in the ''D''3''h'' sites and the cations in ''D''3''d'' sites. The vapor pressure ''P'' (in atm) as a function of temperature ''T'' (in
kelvin The kelvin, symbol K, is the primary unit of temperature in the International System of Units (SI), used alongside its prefixed forms and the degree Celsius. It is named after the Belfast-born and University of Glasgow-based engineer and ...
), in the range , is well approximated by the formula : \ln P = 23.2348 - \frac being about 48 torr at 0 °C, 424 torr at 25 °C, and 760 torr at 32 °C (9 °C below the melting point).A. H. McDaniel, J. A. Davidson, C. A. Cantrell, R. E. Shetter, and J. G. Calvert (1988): "Enthalpies of formation of dinitrogen pentoxide and the nitrate free radical". ''Journal of Physical Chemistry'', volume 92, issue 14, pages 4172–4175. In the gas phase, or when dissolved in nonpolar
solvent A solvent (s) (from the Latin '' solvō'', "loosen, untie, solve") is a substance that dissolves a solute, resulting in a solution. A solvent is usually a liquid but can also be a solid, a gas, or a supercritical fluid. Water is a solvent for ...
s such as
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 ...
, the compound exists as covalently-bonded molecules . In the gas phase, theoretical calculations for the minimum-energy configuration indicate that the angle in each wing is about 134° and the angle is about 112°. In that configuration, the two groups are rotated about 35° around the bonds to the central oxygen, away from the plane. The molecule thus has a propeller shape, with one axis of 180° rotational symmetry (''C''2) S. Parthiban, B. N. Raghunandan, and R.Sumathi (1996): "Structures, energies and vibrational frequencies of dinitrogen pentoxide". ''Journal of Molecular Structure: THEOCHEM'', volume 367, pages 111–118. When gaseous is cooled rapidly ("quenched"), one can obtain the metastable molecular form, which exothermically converts to the ionic form above −70 °C. Gaseous absorbs
ultraviolet light Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nm (with a corresponding frequency around 30  PHz) to 400 nm (750  THz), shorter than that of visible light, but longer than X-rays. UV radiatio ...
with dissociation into the
free radical A daughter category of ''Ageing'', this category deals only with the biological aspects of ageing. Ageing Ailments of unknown cause Biogerontology Biological processes Causes of death Cellular processes Gerontology Life extension Metabo ...
s
nitrogen dioxide Nitrogen dioxide is a chemical compound with the formula . It is one of several nitrogen oxides. is an intermediate in the industrial synthesis of nitric acid, millions of tons of which are produced each year for use primarily in the productio ...
and nitrogen trioxide (uncharged nitrate). The absorption spectrum has a broad band with maximum at wavelength 160  nm.Bruce A. Osborne, George Marston, L. Kaminski, N. C. Jones, J. M. Gingell, Nigel Mason, Isobel C. Walker, J. Delwiche, and M.-J. Hubin-Franskin (2000): "Vacuum ultraviolet spectrum of dinitrogen pentoxide". ''Journal of Quantitative Spectroscopy and Radiative Transfer'', volume 64, issue 1, pages 67–74.


Preparation

A recommended laboratory synthesis entails dehydrating
nitric acid Nitric acid is the inorganic compound with the formula . It is a highly corrosive mineral acid. The compound is colorless, but older samples tend to be yellow cast due to decomposition into oxides of nitrogen. Most commercially available ni ...
() with phosphorus(V) oxide: : Another laboratory process is the reaction of lithium nitrate and bromine pentafluoride , in the ratio exceeding 3:1. The reaction first forms
nitryl fluoride Nitryl fluoride, NO2F, is a colourless gas and strong oxidizing agent, which is used as a fluorinating agent and has been proposed as an oxidiser in rocket propellants (though never flown). It is a molecular species, not ionic, consistent with it ...
that reacts further with the lithium nitrate: : : The compound can also be created in the gas phase by reacting
nitrogen dioxide Nitrogen dioxide is a chemical compound with the formula . It is one of several nitrogen oxides. is an intermediate in the industrial synthesis of nitric acid, millions of tons of which are produced each year for use primarily in the productio ...
or with
ozone Ozone (), or trioxygen, is an inorganic molecule with the chemical formula . It is a pale blue gas with a distinctively pungent smell. It is an allotrope of oxygen that is much less stable than the diatomic allotrope , breaking down in the l ...
:Francis Yao, Ivan Wilson, and Harold Johnston (1982): "Temperature-dependent ultraviolet absorption spectrum for dinitrogen pentoxide". ''Journal of Physical Chemistry'', volume 86, issue 18, pages 3611–3615. : However, the product catalyzes the rapid decomposition of ozone: : Dinitrogen pentoxide is also formed when a mixture of oxygen and nitrogen is passed through an electric discharge.William W. Wilson and Karl O. Christe (1987): "Dinitrogen Pentoxide. New Synthesis and Laser Raman Spectrum". ''Inorganic Chemistry'', volume 26, pages 1631–1633. Another route is the reactions of Phosphoryl chloride or
nitryl chloride Nitryl chloride is a volatile inorganic compound with formula ClNO2. At standard conditions it is a gas. Formation Nitryl chloride can be formed in the reaction of dinitrogen pentoxide with chlorides or hydrogen chloride: :N2O5 + 2HCl → 2ClNO2 ...
with
silver nitrate Silver nitrate is an inorganic compound with chemical formula . It is a versatile precursor to many other silver compounds, such as those used in photography. It is far less sensitive to light than the halides. It was once called ''lunar causti ...


Reactions

Dinitrogen pentoxide reacts with water ( hydrolyses) to produce
nitric acid Nitric acid is the inorganic compound with the formula . It is a highly corrosive mineral acid. The compound is colorless, but older samples tend to be yellow cast due to decomposition into oxides of nitrogen. Most commercially available ni ...
. Thus, dinitrogen pentoxide is the anhydride of nitric acid: : Solutions of dinitrogen pentoxide in nitric acid can be seen as nitric acid with more than 100% concentration. The phase diagram of the system − shows the well-known negative
azeotrope An azeotrope () or a constant heating point mixture is a mixture of two or more liquids whose proportions cannot be altered or changed by simple distillation.Moore, Walter J. ''Physical Chemistry'', 3rd e Prentice-Hall 1962, pp. 140–142 This ...
at 60% (that is, 70% ), a positive azeotrope at 85.7% (100% ), and another negative one at 87.5% ("102% ").L. Lloyd and P. A. H. Wyatt (1955): "The vapour pressures of nitric acid solutions. Part I. New azeotropes in the water–dinitrogen pentoxide system". ''Journal of the Chemical Society (Resumed)'', volume 1955, pages 2248–2252. The reaction with
hydrogen chloride The compound hydrogen chloride has the chemical formula and as such is a hydrogen halide. At room temperature, it is a colourless gas, which forms white fumes of hydrochloric acid upon contact with atmospheric water vapor. Hydrogen chlorid ...
also gives nitric acid and
nitryl chloride Nitryl chloride is a volatile inorganic compound with formula ClNO2. At standard conditions it is a gas. Formation Nitryl chloride can be formed in the reaction of dinitrogen pentoxide with chlorides or hydrogen chloride: :N2O5 + 2HCl → 2ClNO2 ...
:Robert A. Wilkins Jr. and I. C. Hisatsune (1976): "The Reaction of Dinitrogen Pentoxide with Hydrogen Chloride". ''Industrial & Engineering Chemistry Fundamentals'', volume 15, issue 4, pages 246–248. : Dinitrogen pentoxide eventually decomposes at room temperature into and . Decomposition is negligible if the solid is kept at 0 °C, in suitably inert containers. Dinitrogen pentoxide reacts with
ammonia Ammonia is an inorganic compound of nitrogen and hydrogen with the formula . A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct pungent smell. Biologically, it is a common nitrogenous ...
to give several products, including
nitrous oxide Nitrous oxide (dinitrogen oxide or dinitrogen monoxide), commonly known as laughing gas, nitrous, or nos, is a chemical compound, an oxide of nitrogen with the formula . At room temperature, it is a colourless non-flammable gas, and ha ...
,
ammonium nitrate Ammonium nitrate is a chemical compound with the chemical formula . It is a white crystalline salt consisting of ions of ammonium and nitrate. It is highly soluble in water and hygroscopic as a solid, although it does not form hydrates. It is ...
,
nitramide Nitramide is a chemical compound with the molecular formula H2NNO2. Organyl derivatives of nitramide, RNHNO2 are termed nitroamines, and are widely used as explosives: examples include RDX and HMX. It is an isomer of hyponitrous acid. Struct ...
and
ammonium dinitramide Ammonium dinitramide (ADN) is the ammonium salt of dinitraminic acid. ADN decomposes under heat to leave only nitrogen, oxygen, and water. The ions are the ammonium ion NH4+ and the dinitramide N(NO2)2−. It makes an excellent solid rocket oxi ...
, depending on reaction conditions.C. Frenck and W. Weisweiler (2002): "Modeling the Reactions Between Ammonia and Dinitrogen Pentoxide to Synthesize Ammonium Dinitramide (ADN)". ''Chemical Engineering & Technology'', volume 25, issue 2, pages 123–128.


Decomposition of dinitrogen pentoxide at high temperatures

Dinitrogen pentoxide between high temperatures of , is decomposed in two successive stoichiometric steps: : : In the shock wave, has decomposed stoichiometrically into
nitrogen dioxide Nitrogen dioxide is a chemical compound with the formula . It is one of several nitrogen oxides. is an intermediate in the industrial synthesis of nitric acid, millions of tons of which are produced each year for use primarily in the productio ...
and
oxygen Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements ...
. At temperatures of 600 K and higher, nitrogen dioxide is unstable with respect to
nitrogen oxide Nitrogen oxide may refer to a binary compound of oxygen and nitrogen, or a mixture of such compounds: Charge-neutral *Nitric oxide (NO), nitrogen(II) oxide, or nitrogen monoxide * Nitrogen dioxide (), nitrogen(IV) oxide * Nitrogen trioxide (), or ...
and oxygen. The thermal decomposition of 0.1 mM nitrogen dioxide at 1000 K is known to require about two seconds.Schott, G., & Davidson, N. (1958). Shock Waves in Chemical Kinetics: The Decomposition of N2O5 at High Temperatures. Journal of the American Chemical Society, 80(8), 1841–1853.


Decomposition of dinitrogen pentoxide in carbon tetrachloride at 30 °C

Apart from the decomposition of at high temperatures, it can also be decomposed 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 ...
at .J.,Jaime, R. (2008)
Determinación de orden de reacción haciendo uso de integrales definidas
Universidad Nacional Autónoma de Nicaragua, Managua.
Both and are soluble in and remain in solution while oxygen is insoluble and escapes. The volume of the oxygen formed in the reaction can be measured in a gas burette. After this step we can proceed with the decomposition, measuring the quantity of that is produced over time because the only form to obtain is with the decomposition. The equation below refers to the decomposition of in : : And this reaction follows the first order
rate law In chemistry, the rate law or rate equation for a reaction is an equation that links the initial or forward reaction rate with the concentrations or pressures of the reactants and constant parameters (normally rate coefficients and partial react ...
that says: :-\frac = k mathrm/math>


Decomposition of nitrogen pentoxide in the presence of nitric oxide

can also be decomposed in the presence of
nitric oxide Nitric oxide (nitrogen oxide or nitrogen monoxide) is a colorless gas with the formula . It is one of the principal oxides of nitrogen. Nitric oxide is a free radical: it has an unpaired electron, which is sometimes denoted by a dot in its ...
: : The rate of the initial reaction between dinitrogen pentoxide and
nitric oxide Nitric oxide (nitrogen oxide or nitrogen monoxide) is a colorless gas with the formula . It is one of the principal oxides of nitrogen. Nitric oxide is a free radical: it has an unpaired electron, which is sometimes denoted by a dot in its ...
of the elementary unimolecular decomposition.


Applications


Nitration of organic compounds

Dinitrogen pentoxide, for example as a solution in
chloroform Chloroform, or trichloromethane, is an organic compound with formula C H Cl3 and a common organic solvent. It is a colorless, strong-smelling, dense liquid produced on a large scale as a precursor to PTFE. It is also a precursor to various ...
, has been used as a reagent to introduce the functionality in
organic compound In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. Th ...
s. This
nitration In organic chemistry, nitration is a general class of chemical processes for the introduction of a nitro group into an organic compound. The term also is applied incorrectly to the different process of forming nitrate esters between alcohols an ...
reaction is represented as follows: : where Ar represents an arene moiety. The reactivity of the can be further enhanced with strong acids that generate the "super- electrophile" . In this use, has been largely replaced by nitronium tetrafluoroborate . This salt retains the high reactivity of , but it is thermally stable, decomposing at about 180 °C (into and ). Dinitrogen pentoxide is relevant to the preparation of explosives.


Atmospheric occurrence

In the
atmosphere An atmosphere () is a layer of gas or layers of gases that envelop a planet, and is held in place by the gravity of the planetary body. A planet retains an atmosphere when the gravity is great and the temperature of the atmosphere is low. A ...
, dinitrogen pentoxide is an important reservoir of the species that are responsible for
ozone depletion Ozone depletion consists of two related events observed since the late 1970s: a steady lowering of about four percent in the total amount of ozone in Earth's atmosphere, and a much larger springtime decrease in stratospheric ozone (the ozone lay ...
: its formation provides a
null cycle In atmospheric chemistry, a null cycle is a catalytic cycle that simply interconverts chemical species without leading to net production or removal of any component. In the stratosphere, null cycles and when the null cycles are broken are very impor ...
with which and are temporarily held in an unreactive state.
Mixing ratio In chemistry and physics, the dimensionless mixing ratio is the abundance of one component of a mixture relative to that of all other components. The term can refer either to mole ratio (see concentration) or mass ratio (see stoichiometry). In ...
s of several parts per billion by volume have been observed in polluted regions of the nighttime troposphere. Dinitrogen pentoxide has also been observed in the stratosphere at similar levels, the reservoir formation having been postulated in considering the puzzling observations of a sudden drop in stratospheric levels above 50 °N, the so-called ' Noxon cliff'. Variations in reactivity in
aerosol An aerosol is a suspension of fine solid particles or liquid droplets in air or another gas. Aerosols can be natural or anthropogenic. Examples of natural aerosols are fog or mist, dust, forest exudates, and geyser steam. Examples of anthropogen ...
s can result in significant losses in tropospheric
ozone Ozone (), or trioxygen, is an inorganic molecule with the chemical formula . It is a pale blue gas with a distinctively pungent smell. It is an allotrope of oxygen that is much less stable than the diatomic allotrope , breaking down in the l ...
,
hydroxyl radical The hydroxyl radical is the diatomic molecule . The hydroxyl radical is very stable as a dilute gas, but it decays very rapidly in the condensed phase. It is pervasive in some situations. Most notably the hydroxyl radicals are produced from the ...
s, and concentrations. Two important reactions of in atmospheric aerosols are hydrolysis to form
nitric acid Nitric acid is the inorganic compound with the formula . It is a highly corrosive mineral acid. The compound is colorless, but older samples tend to be yellow cast due to decomposition into oxides of nitrogen. Most commercially available ni ...
and reaction with
halide In chemistry, a halide (rarely halogenide) is a binary chemical compound, of which one part is a halogen atom and the other part is an element or radical that is less electronegative (or more electropositive) than the halogen, to make a flu ...
ions, particularly , to form molecules which may serve as precursors to reactive chlorine atoms in the atmosphere.


Hazards

is a strong oxidizer that forms explosive mixtures with organic compounds and
ammonium The ammonium cation is a positively-charged polyatomic ion with the chemical formula or . It is formed by the protonation of ammonia (). Ammonium is also a general name for positively charged or protonated substituted amines and quaterna ...
salts. The decomposition of dinitrogen pentoxide produces the highly toxic
nitrogen dioxide Nitrogen dioxide is a chemical compound with the formula . It is one of several nitrogen oxides. is an intermediate in the industrial synthesis of nitric acid, millions of tons of which are produced each year for use primarily in the productio ...
gas.


References

{{DEFAULTSORT:Dinitrogen Pentoxide Nitrogen oxides Acid anhydrides Acidic oxides Nitrates Nitronium compounds