Chapter 14, Problem 14.45P

Interpretation Introduction

(a)

Interpretation:

Total number of Π electrons present in a polycyclic hydrocarbon coronene is to be determined.

Concept introduction:

Each C=C double bond consists of two Π electrons.

Interpretation Introduction

(b)

Interpretation:

It is to be explained whether the number of Π electrons in the given compound is consistent with the fact that the compound is aromatic.

Concept introduction:

A molecule, to be aromatic, must obey Huckel’s rule $\text{(4n+2)π}$ electrons. Huckel’s rule for aromaticity states that if a species possesses a pi system of molecular orbitals constructed from p-orbitals that are fully conjugated around a ring (${\text{sp}}^2$ hybridized), then the species is:

1. Aromatic, if the number of electrons in that $\text{π}$- system is $2,6,10,14,1,\text{and so on}\text{.}$
2. Antiaromatic if the number of electrons in that $\text{π}$- system is $4,8,12,16,20,\text{and so on}\text{.}$