What aromatic compounds follow Hückel's rule?

All aromatic compounds follow Hückel's rule.

Hückel's rule states that a planar, cyclic, conjugated molecule is aromatic if it contains 4##n## + 2 π electrons, where ##n## = 0 or any positive integer.

See

##n## = 1

The most common examples have ##n## = 1. These include

a. Benzene and its derivatives

b. Six-membered heterocyclics like pyridine and pyrimidine

c. Five membered heterocyclics like pyrrole, furan, and thiophene

d. Five-membered anions like cyclopentadienide ion

e. Seven-membered cations like tropylium ion

##n## = 0

cyclopropenyl cation

##n## = 2

These include naphthalene and azulene.

naphthalene and azulene

##n## = 3 and up

These include the annulenes.

[14]-annulene (##n## = 3)

[18]-annulene (##n## = 4)