Chapter 13, Problem 13.11E

Interpretation Introduction

Interpretation:

The significance of the number in the bottom right position of the general form of the $S_n$ operation is to be stated.

Concept introduction:

Axis of symmetry is defined as an axis around which a rotation by $\raisebox{1ex}{${360}^{\text{ο}}$}\!\left/ \!\raisebox{-1ex}{$n$}\right.$ results in the formation of indistinguishable molecule from the original one.

This is also known as rotational axis and denoted by $C_n$.

An improper axis of symmetry is the symmetry operation denoted by $S_n$. It is a combination of a $C_n$ rotation followed by reflection by a plane, which is perpendicular to the axis.