Question

What are the necessary conditions for any system to be aromatic?

Answer 1

A compound is said to be aromatic if it satisfies the following three conditions:

1. It should have a planar structure.
2. The π–electrons of the compound are completely delocalized in the ring.
3. The total number of π–electrons present in the ring should be equal to (4n + 2), where n = 0, 1, 2 … etc. This is known as Huckel’s rule.

Answer 2

The necessary conditions for a molecule to be aromatic are:

• It should have a single cyclic cloud of delocalised n-electrons above and below the plane of the molecule.
• It should be planar. This is because complete delocalization of n-electrons is possible only if the ring is planar to allow cyclic overlap of p-orbitals.
• It should contain Huckel number of electrons, i.e., (4n + 2) n-electrons where n = 0, 1, 2, 3 etc.
  A molecule which does not satisfy any one or more of the above conditions is said to be non-aromatic.