Question

huckle rule. explain?​

Answer 1

In organic chemistry, Hückel's rule estimates whether a planar ring molecule will have aromatic properties

a cyclic ring molecule follows Hückel's rule when the number of its π-electrons equals 4n + 2 where n is a non-negative integer, although clearcut examples are really only established for values of n = 0 up to about n = 6.

Aromatic compounds are more stable than theoretically predicted using hydrogenation data of simple alkenes; the additional stability is due to the delocalized cloud of electrons, called resonance energy. Criteria for simple aromatics are:

the molecule must have 4n + 2 electrons in a conjugated system of p orbitals (usually on sp2-hybridized atoms, but sometimes sp-hybridized);

the molecule must be (close to) planar (p orbitals must be roughly parallel and able to interact, implicit in the requirement for conjugation);

the molecule must be cyclic (as opposed to linear);

the molecule must have a continuous ring of p atomic orbitals (there cannot be any sp3 atoms in the ring, nor do exocyclic p orbitals count).