Chapter 10, Problem 10.51P

Interpretation Introduction

Interpretation:

On solidification of ${\text{PCl}}_5$, the change in molecular shape and change in $\text{Cl}-\text{P}-\text{Cl}$ angle is to be determined.

Concept introduction:

VSEPR theory is based on the repulsions between the electrons pair in the valence shell. According to VSEPR theory, the shape of a molecule depends on the position of the electron pairs to minimize the repulsion, and maximize the stability.

According to VSEPR theory, the table for molecular geometries when the central atom has no lone pair is as follows:

$\begin{array}{ccc}\text{Electron}\text{groups}& \text{Geometry}& \text{Ideal bond angle}\\ 2& \text{Linear}& 180°\\ 3& \text{Trigonal}\text{Planar}& 120°\\ 4& \text{Tetrahedral}& 109.5°\\ 5& \text{Trigonal}\text{bipyramidal}& 90°,120°\\ 6& \text{Octahedral}& 90°\end{array}$