Chapter 17, Problem 17.15P

Interpretation Introduction

Interpretation:

To explain why a neutral aromatic heterocycle in a five-membered ring can have only one oxygen atom but two or more nitrogen atoms.

Concept introduction:

To be aromatic a molecule must possess,

A molecule must be cyclic, planar, completely conjugated, and contain a particular number of pi electrons. To be aromatic, each p orbital must overlap with p orbitals on two adjacent atoms

All adjacent p orbitals must be aligned so that the 1t electron density can be delocalized.

Aromatic compounds must have a p orbital on every atom in the ring. A molecule must satisfy Huckel's rule, and contain a particular number of pi electrons