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 C_2v point group symmetry.

Nitrogen dioxide

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 Nitrogen dioxide
Other names Nitrogen(IV) oxide,[1] deutoxide of nitrogen
Identifiers
CAS Number	10102-44-0 Y
3D model (JSmol)	Interactive image Interactive image
ChEBI	CHEBI:33101 Y
ChemSpider	2297499 Y
ECHA InfoCard	100.030.234
EC Number	233-272-6
Gmelin Reference	976
PubChem CID	3032552
RTECS number	QW9800000
UNII	S7G510RUBH N
UN number	1067
CompTox Dashboard (EPA)	DTXSID7020974
InChI InChI=1S/NO2/c2-1-3 Y Key: JCXJVPUVTGWSNB-UHFFFAOYSA-N Y InChI=1/NO2/c2-1-3 Key: JCXJVPUVTGWSNB-UHFFFAOYAA
SMILES N(=O)[O] [N+](=O)[O-]
Properties
Chemical formula	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]
Solubility in water	Hydrolyses
Solubility	Soluble in CCl 4, nitric acid,[3] chloroform
Vapor pressure	98.80 kPa (at 20 °C)
Magnetic susceptibility (χ)	+150.0·10−6 cm3/mol[4]
Refractive index (nD)	1.449 (at 20 °C)
Structure
Point group	C2v
Molecular shape	Bent
Thermochemistry[5]
Heat capacity (C)	37.2 J/(mol·K)
Std molar entropy (So298)	240.1 J/(mol·K)
Std enthalpy of formation (ΔfH⦵298)	+33.2 kJ/mol
Hazards
Occupational safety and health (OHS/OSH):
Main hazards	Poison, oxidizer
GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H270, H314, H330
Precautionary statements	P220, P260, P280, P284, P305+P351+P338, P310
NFPA 704 (fire diamond)	3 0 2 OX
Lethal dose or concentration (LD, LC):
LC50 (median concentration)	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]
LCLo (lowest published)	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
Related nitrogen oxides	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 ?) Infobox references

It is included in the NO_x family of atmospheric pollutants.