Chapter 14, Problem 23P

Interpretation Introduction

Interpretation:

The aromatic nature of pentalene and heptalene needs to be explained on the basis of Huckel’s rule.

Concept introduction:

In accordance to the Huckel’s rule, aromatic compounds contain a planar ring and have a conjugated pi system with $(4n+2)\pi$ lectrons, where $n=0,1,2,3,\mathrm{...}$

Aromatic compounds contain conjugated pi bonds.

All the atoms in the ring have an unhybridized $p$ orbital.

Antiaromatic compounds contain $(4n)\pi$ lectrons. They are very unstable and are highly reactive.