State Hückel’s rule

Hückel's rule states that a molecule is considered to be aromatic if it follows the following criteria:

1. The molecule must be cyclic, meaning it forms a closed loop of atoms.
2. The molecule must be planar, meaning all the atoms lie in the same plane.
3. The molecule must have a continuous system of overlapping p orbitals, which are the orbitals involved in the delocalization of electrons.
4. The molecule must have 4n+2 π electrons, where n is an integer. This is known as the "4n+2 rule".

By applying Hückel's rule, we can determine whether a molecule is aromatic or not based on its structure and the number of π electrons it possesses.