Sistem Nota Atas Talian Pelajar Versi 2.0

characteristic of an aromatic compound 

1. They are cyclic

2. They are conjugated all around the ring. The easiest way to put it is this: every atom in the ring must be able to participate in resonance. So atoms that have pi bonds,  Carbocations, or lone pair are OK. but atoms with four single bonds are out. 

3. The molecule must have (4n +2) pi electrons. This is just a different way of expressing the series (2,6,10,14,18 etc). Huckel's Rule states that all aromatic molecules satisfy this condition. Now,  pi electrons can either come from double bonds or from lone pairs that can align themselves with the pi system. 

4. The molecule must be flat.