Question

What are aromatic compounds?

Answer 1

See below

Explanation:

In very short aromatic compound should fulfill the following criteria:-
1)the structure must be cyclic,containing some numbers of conjugated `pi` bonds.
2) each atom in the ring must have an unhybridised p orbital. (the ring atoms are usually `sp²` hybridized or occasionally sp hybridized.)
3) the unhybridized p orbitals must overlap to form a continuous ring of parallel orbitals.In most cases ,the structure must be plannar or nearly plannar for effective overlap to occur.
4) Delocalization of `pi` electrons over the ring must lower the electronic energy.

However "Erich Huckel" developed a very shortcut for predicting a aromatic compound. The rule tells us if the number of `pi` electron in the cyclic continous ring system is `4N+2` then compound is aromatic.