Question #5f272

1 Answer
Mar 17, 2015

Nitrogen dioxide, or NO2, is an odd-electron molecule, i.e. the number of valence electrons the molecule has is not an even number.

More specifically, nitrogen dioxide has a total of 17 valence electrons - 5 from nitrogen and 6 from each of the two oxygen atoms that comprise the molecule.

Now, VSEPR Theory can be extended to accomodate odd-electron molecules. In this case, the nitrogen dioxide molecule is considered to have a AX2E0.5 geometry, which is right between AX2E0 - linear, and AX2E1 - bent.

http://www.elmhurst.edu/~chm/vchembook/206bent.html

The molecule's geometry will still be closer to bent, but the bond angle will be larger than the ideal 120 such a geometry predicts, mostly because the oxygen atoms experience less repulsion from the single electron present on the nitrogen atom.

The actual bond angle for nitrogen dioxide is 134. By comparison, the angle found in the nitrite ion, or NO2, is 115.4, because now nitrogen has attached a full lone pair of electrons that experience greater repulsion with the oxygen atoms.