Question

Show wheter the following compounds exhibit aromaticity.
(a) Pyridine, (b) Cyclo-octateraene, ( c) Pyrrole, (d) Cyclobutaiene, ( e) Furan, (f) Thiophene.

Answer 1

(a) Pyridine has the following structrue :

It has three double bonds, i.e., `6pi` electrons.
`4pi+2=6`
`4pi=6-2=4`
n=1
Therefore, pyridine shows aromaticity.
(b) Cyclo-octatetrance has the following structure:

It four double bonds, i.e., `8pi` electros.
`4pi+2=8`
`4pi+8-2=6`
`n=1.5("not an integer")`
Therefore, cyclo-octatetraene does not show aromaticity.
( c)