Nitrogen dioxide
Nitrogen dioxide is a chemical compound. Its chemical formula is NO2. It contains nitrogen and oxide ions. The nitrogen is in the +4 oxidation state.
Properties
Nitrogen Dioxide is a reddish-brown gas with a distinct, pungent odor similar to that of Chlorine. It causes significant and damaging pulmonary effects when it is inhaled, due to the formation of both Nitric (HNO3) & Nitrous (HNO2) acids when it reacts with Water present in the lungs. When Nitrogen Dioxide is compressed or cooled to near 0° C, two molecules of the Dioxide bond, forming the colorless Dinitrogen Tetroxide. It is a strong oxidizing agent. Upon heating, Nitrogen Dioxide decomposes back into lower oxides of Nitrogen (NO) as well as Oxygen. It reacts with iodides to form nitrites and elemental iodine. The presence of NO2 in concentrated Nitric acid causes the acid to take on a yellow color, depending on the concentration of the dissolved gas.
Preparation
Nitrogen dioxide is normally made by oxidation of nitric oxide by oxygen in air. It can also be made by heating some nitrates. It can be made by reacting concentrated nitric acid with copper or tin.
Uses
It is used to make nitric acid by dissolving it in water. Nitric oxide is also released.
Safety
Nitrogen dioxide is very toxic. It has a foul odor, which aids in its detection. Much care should be taken to avoid contact with this compound.
Nitrogen Dioxide Media
A "fox tail" over Nizhniy Tagil Iron and Steel Works
Nitrogen dioxide 2011 tropospheric column density.
Pathways indicated by a dotted line are those for which evidence is limited to findings from experimental animal studies, while evidence from controlled human exposure studies is available for pathways indicated by a solid line. Dashed lines indicate proposed links to the outcomes of asthma exacerbation and respiratory tract infections.
Nitrogen dioxide diffusion tube for air quality monitoring. Positioned in the City of London.
