Lewis Structures and Reactivity #1: The Case of Nitrogen Dioxide (NO2) | Chemistry Net

Lewis Structures and Reactivity #1: The Case of Nitrogen Dioxide (NO2)

The Lewis structures of NO2 were derived in a previous article entitled “Lewis Structures and the Octet Rule using a simple procedure. The structures indicate that NO2 is an odd-electron molecule, a free radical as it is called. As a matter of fact the odd electron in the molecule appears to be somewhat local to the nitrogen atom.

How can I draw Lewis structures of NO2
Fig. 1: Resonance structures of nitrogen dioxide NO2
The above resonance Lewis structures in a sense explain the reactivity of NO2. As an odd electron species is expected to be very reactive trying either to get rid off or to find an extra electron so that it will become more stable (octet rule is obeyed in the last case). As a consequence, it readily reacts with another molecule of NO2 to form a dimer, N2O4. The dimerization process (equilibrium) is so facile that it cannot be retained in pure form at ordinary temperatures.

Dimerization of NO2
    Fig. 2: Formation of N2O4  from NO2

The video below shows the eqiliburium that is readily established between NO2 and N2O4

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