Dinitrogen pentoxide

Dinitrogen pentoxide
Full structural formula with dimensions
Ball-and-stick model
Names
IUPAC name
Dinitrogen pentoxide
Other names
Nitric anhydride
Nitronium nitrate
Nitryl nitrate
DNPO
Anhydrous nitric acid
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
ECHA InfoCard 100.030.227 Edit this at Wikidata
EC Number
  • 233-264-2
UNII
  • InChI=1S/N2O5/c3-1(4)7-2(5)6 checkY
    Key: ZWWCURLKEXEFQT-UHFFFAOYSA-N checkY
  • InChI=1/N2O5/c3-1(4)7-2(5)6
    Key: ZWWCURLKEXEFQT-UHFFFAOYAN
  • gas phase: [O-][N+](=O)O[N+]([O-])=O
  • solid phase: [O]=[N+]=[O].[N+](=O)([O-])[O-]
Properties
N2O5
Molar mass 108.01 g/mol
Appearance white solid
Density 2.0 g/cm3[1]
Boiling point 33 °C (91 °F; 306 K) sublimes[1]
reacts to give HNO3
Solubility soluble in chloroform
negligible in CCl4
−35.6×10−6 cm3 mol−1 (aq)
1.39 D
Structure[2]
Hexagonal, hP14
P63/mmc No. 194
a = 0.54019 nm, c = 0.65268 nm
2
planar, C2v (approx. D2h)
N–O–N ≈ 180°
Thermochemistry[3]
143.1 J K−1 mol−1 (s)
95.3 J K−1 mol−1 (g)
178.2 J K−1 mol−1 (s)
355.7 J K−1 mol−1 (g)
−43.1 kJ/mol (s)
+13.3 kJ/mol (g)
113.9 kJ/mol (s)
+117.1 kJ/mol (g)
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
 strong oxidizer, forms strong acid in contact with water
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 4: Very short exposure could cause death or major residual injury. E.g. VX gasFlammability 0: Will not burn. E.g. waterInstability 2: Undergoes violent chemical change at elevated temperatures and pressures, reacts violently with water, or may form explosive mixtures with water. E.g. white phosphorusSpecial hazard W+OX: Reacts with water in an unusual or dangerous manner AND is oxidizer
4
0
2
W
OX
Flash point Non-flammable
Related compounds
Nitrous oxide
Nitric oxide
Dinitrogen trioxide
Nitrogen dioxide
Dinitrogen tetroxide
Related compounds
 Nitric acid
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☒N verify (what is checkY☒N ?)

Dinitrogen pentoxide (also known as nitrogen pentoxide or nitric anhydride) is the chemical compound with the formula N2O5. It is one of the binary nitrogen oxides, a family of compounds that contain only nitrogen and oxygen. It exists as colourless crystals that sublime slightly above room temperature, yielding a colorless gas.[4]

Dinitrogen pentoxide is an unstable and potentially dangerous oxidizer that once was used as a reagent when dissolved in chloroform for nitrations but has largely been superseded by nitronium tetrafluoroborate (NO2BF4).

N2O5 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 [NO2]+ and nitrate anions [NO3]−; but in the gas phase and under some other conditions it is a covalently-bound molecule.[5]

  1. ^ a b Haynes, p. 4.76
  2. ^ Simon, Arndt; Horakh, Jörg; Obermeyer, Axel; Borrmann, Horst (1992). "Kristalline Stickstoffoxide — Struktur von N2O3 mit einer Anmerkung zur Struktur von N2O5". Angewandte Chemie (in German). 104 (3). Wiley: 325–327. Bibcode:1992AngCh.104..325S. doi:10.1002/ange.19921040321.
  3. ^ Haynes, p. 5.29
  4. ^ Connell, Peter Steele. (1979) The Photochemistry of Dinitrogen Pentoxide. Ph. D. thesis, Lawrence Berkeley National Laboratory.
  5. ^ Angus, W.R.; Jones, R.W.; Phillips, G.O. (1949). "Existence of Nitrosyl Ions (NO+) in Dinitrogen Tetroxide and of Nitronium Ions (NO2+) in Liquid Dinitrogen Pentoxide". Nature. 164 (4167): 433. Bibcode:1949Natur.164..433A. doi:10.1038/164433a0. PMID 18140439. S2CID 4136455.