Dinitrogen tetroxide

Dinitrogen tetroxide
Full structural formula
Full structural formula
Space-filling model
Space-filling model
Nitrogen dioxide at different temperatures
Nitrogen dioxide at −196 °C, 0 °C, 23 °C, 35 °C, and 50 °C. (NO
2) converts to the colorless dinitrogen tetroxide (N
2O
4) at low temperatures, and reverts to NO
2 at higher temperatures.
Names
IUPAC name
Dinitrogen tetroxide
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
ECHA InfoCard 100.031.012 Edit this at Wikidata
EC Number
  • 234-126-4
2249
RTECS number
  • QW9800000
UNII
UN number 1067
  • InChI=1S/N2O4/c3-1(4)2(5)6 checkY
    Key: WFPZPJSADLPSON-UHFFFAOYSA-N checkY
  • InChI=1/N2O4/c3-1(4)2(5)6
    Key: WFPZPJSADLPSON-UHFFFAOYAS
  • [O-][N+](=O)[N+]([O-])=O
Properties
N2O4
Molar mass 92.010 g·mol−1
Appearance White solid, colorless liquid, orange gas
Density 1.44246 g/cm3 (liquid, 21 °C)
Melting point −11.2 °C (11.8 °F; 261.9 K) and decomposes to NO2
Boiling point 21.69 °C (71.04 °F; 294.84 K)
Reacts to form nitrous and nitric acids
Vapor pressure 96 kPa (20 °C)[1]
−23.0·10−6 cm3/mol
1.00112
Structure
Planar, D2h
small, non-zero
Thermochemistry
304.29 J/K⋅mol[2]
+9.16 kJ/mol[2]
Hazards
GHS labelling:
GHS03: OxidizingGHS05: CorrosiveGHS06: ToxicGHS07: Exclamation mark
Danger
H270, H314, H330, H335, H336
P220, P244, P260, P261, P264, P271, P280, P284, P301+P330+P331, P303+P361+P353, P304+P340, P305+P351+P338, P310, P312, P320, P321, P363, P370+P376, P403, P403+P233, P405, P410+P403, P501
NFPA 704 (fire diamond)
[3][4]
NFPA 704 four-colored diamondHealth 3: Short exposure could cause serious temporary or residual injury. E.g. chlorine gasFlammability 0: Will not burn. E.g. waterInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazard OX: Oxidizer. E.g. potassium perchlorate
3
0
0
OX
Flash point Non-flammable
Safety data sheet (SDS) External SDS
Related compounds
Related compounds
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 tetroxide, commonly referred to as nitrogen tetroxide (NTO), and occasionally (usually among ex-USSR/Russian rocket engineers) as amyl, is the chemical compound N2O4. It is a useful reagent in chemical synthesis. It forms an equilibrium mixture with nitrogen dioxide. Its molar mass is 92.011 g/mol.

Dinitrogen tetroxide is a powerful oxidizer that is hypergolic (spontaneously reacts) upon contact with various forms of hydrazine, which has made the pair a common bipropellant for rockets.

  1. ^ International Chemical Safety Card https://www.ilo.org/dyn/icsc/showcard.display?p_lang=en&p_card_id=0930&p_version=2
  2. ^ a b P.W. Atkins and J. de Paula, Physical Chemistry (8th ed., W.H. Freeman, 2006) p.999
  3. ^ "Chemical Datasheet: Nitrogen tetroxide". CAMEO Chemicals NOAA. Retrieved 8 September 2020.
  4. ^ "Compound Summary: Dinitrogen tetroxide". PubChem. Retrieved 8 September 2020.