Nitrogen dioxide

Nitrogen dioxide is a chemical compound with the formula NO
2
. It is one of several nitrogen oxides. NO
2
is an intermediate in the industrial synthesis of nitric acid, millions of tons of which are produced each year for use primarily in the production of fertilizers. At higher temperatures it is a reddish-brown gas. It can be fatal if inhaled in large quantity.[8] Nitrogen dioxide is a paramagnetic, bent molecule with C2v point group symmetry.

Nitrogen dioxide
Skeletal formula of nitrogen dioxide with some measurementsEP
Spacefill model of nitrogen dioxide

NO
2
converts to the colorless dinitrogen tetroxide (N
2
O
4
) at low temperatures and reverts to NO
2
at higher temperatures.
Names
IUPAC name
Nitrogen dioxide
Other names
Nitrogen(IV) oxide,[1] deutoxide of nitrogen
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
ECHA InfoCard 100.030.234
EC Number
  • 233-272-6
976
RTECS number
  • QW9800000
UNII
UN number 1067
  • InChI=1S/NO2/c2-1-3 Y
    Key: JCXJVPUVTGWSNB-UHFFFAOYSA-N Y
  • InChI=1/NO2/c2-1-3
    Key: JCXJVPUVTGWSNB-UHFFFAOYAA
  • N(=O)[O]
  • [N+](=O)[O-]
Properties
NO
2
Molar mass 46.006 g/mol[2]
Appearance Brown gas[2]
Odor Chlorine-like
Density 1.880 g/L[2]
Melting point −9.3 °C (15.3 °F; 263.8 K)[2]
Boiling point 21.15 °C (70.07 °F; 294.30 K)[2]
Hydrolyses
Solubility Soluble in CCl
4
, nitric acid,[3] chloroform
Vapor pressure 98.80 kPa (at 20 °C)
+150.0·10−6 cm3/mol[4]
1.449 (at 20 °C)
Structure
C2v
Bent
Thermochemistry[5]
37.2 J/(mol·K)
240.1 J/(mol·K)
+33.2 kJ/mol
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
Poison, oxidizer
GHS labelling:
Danger
H270, H314, H330
P220, P260, P280, P284, P305+P351+P338, P310
NFPA 704 (fire diamond)
Lethal dose or concentration (LD, LC):
30 ppm (guinea pig, 1 h)
315 ppm (rabbit, 15 min)
68 ppm (rat, 4 h)
138 ppm (rat, 30 min)
1000 ppm (mouse, 10 min)[6]
64 ppm (dog, 8 h)
64 ppm (monkey, 8 h)[6]
NIOSH (US health exposure limits):
PEL (Permissible)
C 5 ppm (9 mg/m3)[7]
REL (Recommended)
ST 1 ppm (1.8 mg/m3)[7]
IDLH (Immediate danger)
13 ppm[7]
Safety data sheet (SDS) ICSC 0930
Related compounds
Dinitrogen pentoxide

Dinitrogen tetroxide
Dinitrogen trioxide
Nitric oxide
Nitrous oxide

Related compounds
Chlorine dioxide
Carbon dioxide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify (what is YN ?)

It is included in the NOx family of atmospheric pollutants.


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