Chapter 1, Problem 1.78AP

Interpretation Introduction

Interpretation:

The bonding of ${\text{PCl}}_{\text{5}}$ is to be described without using d-orbitals.

Concept introduction:

Hybridization is the process of combinations of atomic orbitals forms hybrid orbitals.

sp³ Hybrid orbital:

The combination of one s atomic orbital and three p atomic orbitals forms sp³ hybrid orbital.

sp² Hybrid orbital:

The combination of one s atomic orbital and two p atomic orbitals forms sp² hybrid orbital.

sp Hybrid orbital:

The combination of one s atomic orbital and one p atomic orbitals forms sp hybrid orbital.

According to VSPER theory the bond angle is depends on the valence electron of an atom. Valence electrons may be involved in the formation of single, double, or triple bonds or they may be unshared (lone pair) electrons.

According to VSPER theory,

1. (1) Regions of electron density around the central atom are four, the geometry of the molecule may be tetrahedral and the bond angle is $\text{109}{\text{.5}}^{\text{o}}$.
2. (2) Regions of electron density around the central atom is three, the geometry of the molecule may be trigonal planar and the bond angle is ${\text{120}}^{\text{o}}$.
3. (3) Regions of electron density around the central atom are two, the geometry of the molecule may be linear and the bond angle is ${\text{180}}^{\text{o}}$.

Groups bonded to carbon	Orbital hybridization	Bond angle	Types of bond
4	sp3	109.5o	Four σ bonds
3	sp2	120 o	Three σ bonds and one π bond
2	sp	180 o	Two σ bonds and two π bond