Aromatic Chemistry — the principles

In the early days of organic chemistry, scientists found that a fair number of compounds having pleasant aromatic smells were all derivatives of a six-carbon molecule called benzene, C₆H₆. The benzene part of the molecules seemed surprisingly stable, especially considering how many multiple bonds there would have to be to satisfy the valencies; and for some years there was no satisfactory explanation of the bonding. But during this period the term ‘aromatic’ was applied to many other benzene derivatives, even when they had no smell at all. By the time a suitable description of the bonding in benzene and its derivatives had been produced, the misleading term ‘aromatic’ had become too widely used to be dropped. It is now used to refer to compounds derived from benzene, or benzene-like compounds, with absolutely no reference to their smell. Aromatic compounds may of course have an aromatic smell, but their smell could just as well be foetid, sweet, pungent, or ethereal, or they may have no smell at all.