Chapter 15, Problem 15.39P

Interpretation Introduction

Interpretation:

On the basis of aromaticity theory, the compounds A and B are different and the compounds C and D are the same is to be stated.

Concept introduction:

If a compound is aromatic then it has to follow certain rules. A compound that is cyclic, planar, completely conjugated and follows Huckel’s rule is classified as an aromatic compound. Aromatic compounds follow Huckel’s rule of $\left(4n+2\right)\text{π}$ electrons. The stability of a compound depends upon the number of resonating structures.

If a compound is antiaromatic it has some characteristics features such as they are cyclic, nonplanar, completely conjugated compounds. They do not follow Huckel’s $\left(4n+2\right)\text{π}$ rule. They have $4n\text{π}$ electrons. They are highly unstable and highly reactive. They change their shape to avoid instability.