Huckel's rule

Hückel's rule is a guideline in organic chemistry used to determine if a molecule with a ring structure is aromatic, meaning it has special stability and properties. The rule states that a planar, cyclic molecule with conjugated (alternating double and single) bonds is aromatic if it has a total of (4n + 2) π electrons, where n is a non-negative integer (0, 1, 2, ...). For example, with 2, 6, 10, or 14 π electrons, the molecule is aromatic. This rule helps chemists predict molecule stability based on electron count in ring systems.