Dinitrogen Pentoxide

Dinitrogen pentoxide according to systematic nomenclature. Its chemical formula is (N 2 O 5 ) , also known by the stock nomenclature as nitrogen oxide (V), and by the traditional nomenclature as nitric anhydride, it has an oxidation number of +5. With the exception of the other Nitrogen oxides , which are in a gaseous state, it is present in a solid state, has a weak acid characteristic, and can explode without any apparent external cause. Its importance lies in the fact that it can react in a solution, as well as in the gas phase.


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  • 1 Physical properties
  • 2 Structure
  • 3 Obtaining
    • 1 Natural source of production
  • 4 Chemical properties
    • 1 Decomposition mechanism
  • 5 Use
  • 6 References
  • 7 Sources
  • 8 External link

Physical properties

Dinitrogen pentoxide, with a molar mass of 108.01 g / mol, is a white solid compound, melts at 30.0 ° C, is stable at temperatures below 8 ° C, and must also be in the absence of light solar. In a state of high purity, it forms hard, colorless deliquescent crystals in air.

It can be described as acid anhydride- it is the oxide obtained by removing water from an oxo acid-

2 HNO 3 2 HNO 3 = N 2 O 5 + H 2 O>


Its structure is formed by removal of water from nitric acid, it is an interesting example of a substance whose molecular structural unit is different in the solid state and in the gas
phase. In the gas phase it is made up of covalent molecules, on the contrary, optical and ray studies. X show that the white solid is an ionic compound composed of nitronium ions (NO2) + and nitrate ions (NO3)  . Experimentation indicates that N 2 O 5 must be the ionic compound “nitronium nitrate”, (NO2) + (NO3)  . Nitronium ion is isoelectronic with carbon dioxide and dinitrogen dioxide, has a linear AX 2 structure (ONO). The nitrate ion is isoelectronic with carbon monoxide and boron fluoride and has a flat trigonal structure; but its high volatility shows that the ionic crystal easily passes covalent molecules to the gaseous state.


It is obtained by dehydrating 100% nitric acid with diphosphorous pentoxide (P 4 O 10 )

4HNO 3 (l) + P 4 O 10 (s) = 2N 2 O 5 (s) + 4HPO 3 (l)

, or by the action of the chlorine on the silver nitrate at 60 ° C

2Cl 2 (l) + AgNO 3 (ac) = 2N 2 O 5 (s) + AgCl (ac) + O 2 (g) at 60 ° C


Natural source of production

It is generated in the air at a very low concentration, unless it is emitted by some process (such as a nitric acid producing facility) that is specifically designed to generate it.

Chemical properties

Dinitrogen pentoxide is highly reactive, and forms nitric acid (HNO3) when it decomposes in water.

2 O 5 + H 2 O = 2 HNO 3

it is the most highly ionized form of nitrogen oxide, which gives it a high combustion capacity.
Slowly decomposes at room temperature to obtain nitrogen dioxide and oxygen.

2N 2 O 5 (s) = 4NO 2 (l) + O 2 (g)


Decomposition mechanism

The decomposition mechanism of dinitrogen pentoxide involves transient nitrogen trioxide (NO 3 ). In the first decomposition step N 2 O 5 is in equilibrium with nitrogen dioxide (NO 2 ) and nitrogen trioxide (NO 3 )

1.- N 2 O 5 = 2NO 2 + NO 3 (fast equilibrium)

Some collisions between NO 2 and NO 3 nitrogen trioxide lead to the formation of a molecule of oxygen (O 2 ):>)

2.- NO 2 + NO 3 = NO 2 + NO + O 2 (slow)

A more detailed representation of this step is


Also known as nitrous anhydride, which is an excellent nitrating agent, and is used for the synthesis of most energy materials, which are obtained by the nitration of a variety of substrates such as aromatics, alkanes, alkenes, alcohols, sugars. , oximes, amines and amides.


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