Definition of nitrogen dioxide in US English:

nitrogen dioxide


  • A reddish-brown poisonous gas occurring commonly as an air pollutant, formed by the oxidation of nitric oxide or by combustion in the presence of air. Below 70°F (21°C), nitrogen dioxide is a yellowish-brown liquid.

    Chemical formula: NO₂. It exists in equilibrium with dinitrogen tetroxide, N₂O₄

    • ‘Free radicals such as nitric oxide and nitrogen dioxide show weak attractions toward magnetic fields - they are called paramagnetic.’
    • ‘Increases in ozone, sulphur dioxide, nitrogen dioxide and carbon monoxide are blamed primarily on the motorist.’
    • ‘Levels of nitric oxide, nitrogen dioxide and sulphur dioxide remained at a normally low level.’
    • ‘Nitric oxide and nitrogen dioxide were chemically assayed as nitrite from sorbent tubes by using spectrophotometry.’
    • ‘In these reactions the ozone reacts with nitric oxide to produce nitrogen dioxide.’


nitrogen dioxide

/ˈnaɪtrədʒən daɪˈɑkˌsaɪd//ˈnītrəjən dīˈäkˌsīd/