Nitrous oxide

Structural formula
General
Surname	Nitrous oxide
other names	DNPO Nitric anhydride Nitrogen (V) oxide
Molecular formula	N 2 O 5
Brief description	colorless solid
External identifiers / databases
CAS number 10102-03-1 EC number 233-264-2 ECHA InfoCard 100.030.227 PubChem 66242 Wikidata Q408458
properties
Molar mass	108.01 g · mol -1
Physical state	firmly
density	1.64 g cm −3
Melting point	30-35 ° C
solubility	reacts with water
safety instructions
GHS hazard labeling no classification available
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Dinitrogen pentoxide is the anhydride of nitric acid and belongs to the group of nitrogen oxides .

presentation

Dinitrogen pentoxide can be obtained from nitric acid by dewatering with phosphorus pentoxide .

${\displaystyle \mathrm {6\ HNO_{3}+P_{2}O_{5}\ \longrightarrow \ 2\ H_{3}PO_{4}+3\ N_{2}O_{5}} }$

Nitric acid reacts with diphosphorus pentoxide to form phosphoric acid and nitrous oxide .

Other possibilities for production consist in the reaction of salt-like nitrates or concentrated nitric acid with nitryl fluoride (NO ₂ F) or of the latter with hydrogen fluoride or by oxidation of the NO _2, which is dimer in the gas phase as N ₂ O _4, with ozone.

${\displaystyle \mathrm {2\ NO_{2}+O_{3}\longrightarrow N_{2}O_{5}+O_{2}} }$

From 1983 onwards, technical synthesis was mostly carried out by electrolysis of nitric acid in the presence of nitrous oxide .

${\displaystyle \mathrm {2\ HNO_{3}\longrightarrow N_{2}O_{5}+H_{2}O} }$

properties

Structure of nitrous oxide with bond lengths and angles

Dinitrogen pentoxide forms colorless crystals which violently decompose with water to nitric acid.

${\displaystyle \mathrm {N_{2}O_{5}+H_{2}O\ \longrightarrow \ 2\ HNO_{3}} }$

Dinitrogen pentoxide reacts with water to form nitric acid.

The compound is soluble in chloroform , carbon tetrachloride , trichlorofluoromethane and sulfolane , but the solutions must be cooled to at least 0 ° C. It decomposes to NO ₂ and O ₂ at room temperature . The half-life is about 10 days at 0 ° C and about 10 hours at 20 ° C. If heated rapidly, the decomposition is often explosive.

${\displaystyle \mathrm {2\ N_{2}O_{5}\ \longrightarrow 4\ NO_{2}+O_{2}} }$

In the solid state, nitrous oxide has the ionic structure [NO ₂ ⁺ ] [NO ₃ ^- ] and has a hexagonal crystal structure with the space group P 6 ₃ / mmc (space group no. 194) . It has very strong oxidizing properties.

use

Solutions of pure nitrous oxide in organic solvents (e.g. dichloromethane or trichlorofluoromethane ) are mild nitrating agents that have found wide application.

literature

• Erwin Riedel : Inorganic Chemistry. 5th edition. De Gruyter, Berlin 2002, ISBN 3-11-017439-1 .

Individual evidence

1. ↑ ^{a b c d e f g h} G. Brauer (Ed.): Handbook of Preparative Inorganic Chemistry , 2nd ed., Vol. 1, Academic Press 1963, pp. 489-490.
2. ↑ This substance has either not yet been classified with regard to its hazardousness or a reliable and citable source has not yet been found.
3. ↑ ^{a b} Thomas M. Klapötke : Chemistry of high-energy materials . Walter de Gruyter, 2009, ISBN 978-3-11-021487-1 , p. 142 ( limited preview in Google Book search).
4. ↑ Bruce M. McClelland, Alan D. Richardson, Kenneth Hedberg: A Reinvestigation of the Structure and Torsional Potential of N ₂ O ₅ by Gas-Phase Electron Diffraction Augmented by Ab Initio Theoretical Calculations . In: Helvetica Chimica Acta . tape 84 , no. 6 , 2001, p. 1612-1624 , doi : 10.1002 / 1522-2675 (20010613) 84: 6 <1612 :: AID-HLCA1612> 3.0.CO; 2-K .
5. ↑ Ralf Steudel : Chemistry of Non-Metals: From Structure and Bond to Application . Walter de Gruyter, 2008, ISBN 978-3-11-021128-3 , p. 347 ( limited preview in Google Book search).
6. ^ Jean d'Ans, Ellen Lax, Roger Blachnik: Pocket book for chemists and physicists . Springer DE, 1998, ISBN 3-642-58842-5 , pp. 586 ( limited preview in Google Book search).