Nitrogen dioxide

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Properties

General

Name Nitrogen dioxide
Chemical formula NO2
Appearance brown/orange gas

Physical

Formula weight 46.01 amu
Melting point -263.85 K (9.3 C)
Boiling point -252.00 K (21.15 C)
Density  
Crystal structure  
Solubility  

Thermochemistry

ΔfH0gas   kJ/mol
ΔfH0liquid   kJ/mol
ΔfH0solid   kJ/mol
S0gas, 1 bar   J/mol·K
S0liquid, 1 bar   J/mol·K
S0solid   J/mol·K

Safety

Ingestion  
Inhalation  
Skin  
Eyes  
More info
SI units were used where possible. Unless otherwise stated, standard conditions were used.

Disclaimer and references

The chemical compound nitrogen dioxide is an orange/brown gas and smells rather disgustingly (biting), though characteristical. It is poisonous.

Nitric oxide (NO) spontaneously produces the dioxide when exposed to air:

2 NO + O2 --> NO2

It is also generated in various reactions by nitric acid, e.g. when metals, such as Copper or Silver, are exposed to nitric acid.

It reacts, even at normal temperature & pressure, with water, where it disproportionates to nitric and nitrous acid. That reaction is used in the Ostwald process.

Vapor pressure, mmHg: 400 @ 80 oC
Vapor density (air=1): 1.58
Specific gravity/density: 1.4494 at 20C
Solubility in water: Reacts
Odor threshold: 2.0 mg/m3
Heat of vaporization: 9.110 kcal/mole




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