Chapter 20, Problem 20.26QP

Interpretation Introduction

Interpretation:

The factors that determines whether a given complex will be diamagnetic or paramagnetic has to be given.

Concept Introduction:

Diamagnetic:

The compounds in which all the electrons are paired in their orbitals are considered as diamagnetic compounds. Such compounds will be repelled by the magnetic field.

Paramagnetic:

If a compound consists of one or more unpaired electrons in their valence shell then it is known as paramagnetic compound. Such compounds will be attracted by the magnetic field.

Crystal field splitting:

When ligands approach the central metal atom then the field strength of the ligand splits the outermost valence d orbitals of the central metal atom into two set of orbitals such as ${\text{t}}_{\text{2g}}$ and ${\text{e}}_{\text{g}}$ orbitals. The energy gap between two set of ${\text{t}}_{\text{2g}}$ and ${\text{e}}_{\text{g}}$ orbitals will be more or less based on the extent of splitting which in turn is based on the strength of the ligands. This phenomenon is known as Crystal field splitting.

The following diagram shows the splitting in the octahedral complexes:

Splitting energy is the energy between ${\text{t}}_{\text{2g}}$ and ${\text{e}}_{\text{g}}$ orbitals. The splitting energy distinguishes the energy of ${\text{t}}_{\text{2g}}$ and ${\text{e}}_{\text{g}}$ orbitals. ${\text{t}}_{\text{2g}}$ orbitals are the lower energy orbitals whereas ${\text{e}}_{\text{g}}$ orbitals are the higher energy orbitals. Splitting energy is represented as ${\text{Δ}}_{\text{o}}$ .

Pairing energy is the energy required to pair up electrons in an orbital. It is represented as $\Pi$.