Aromaticity

In organic chemistry, aromaticity is a property of cyclic (ring-shaped), planar (flat) structures with a ring of resonance bonds that gives increased stability compared to other geometric or connective arrangements with the same set of atoms. Aromatic molecules are very stable, and do not break apart easily to react with other substances. Organic compounds that are not aromatic are classified as aliphatic compounds—they might be cyclic, but only aromatic rings have special stability (low reactivity).

Since the most common aromatic compounds are derivatives of benzene, the word aromatic occasionally refers informally to benzene derivatives, and so it was first defined. Nevertheless, many non-benzene aromatic compounds exist.

References

Relevant Sciencemadness threads

• Question on aromaticity in ions
• The aromaticity of halonium ions
• Heterocyclic aromaticity
• Is this an aromatic compound ?