The definition of aromaticity? To be aromatic, a portion of a
molecule must have *all* of the following criteria:

- Cyclic
- At least 1 p orbital on each atom
- Planar (with continuous overlap between p orbitals)
- 4n + 2 electrons total in the pi system, where n is any whole number (0, 1, 2, etc.). This mean that common allowable values for the total number of electrons are 2, 6, 10 and so forth.