Chapter 19, Problem 66E

Interpretation Introduction

Interpretation: The color change of red color ${{\text{[Co(H}}_{\text{2}}{\text{O)}}_{\text{6}}\text{]}}^{\text{2+}}$ to blue color of ${{\text{[CoCl}}_{\text{4}}\text{]}}^{\text{2-}}$ after addition of concentration hydrochloric acid needs to be explained.

Concept Introduction:

Crystal field theory is the theory given to explain the bonding in the coordination complexes. As ligand approaches towards the metal ion, the d-orbital of metal ion divide according to the energy of metal ion. On the basis of energy and degeneracy, the d-orbital can be classified as ${\text{t}}_{\text{2g}}$ and ${\text{e}}_{\text{g}}$ orbitals. The electrons will fill according to their energy levels.

The spectrochemical series can be defined as the series of ligands in order of their ability of splitting the d-orbitals.

It can be used to study the light absorbed by the complexes as it shows the ligands from strong field to weak field.