Difference Between Crystal Field Stabilization Energy and Splitting Energy

The key difference between crystal field stabilization energy and splitting energy is that crystal field stabilization energy refers to the energy difference between the energy of the electron configuration of the ligand and the energy of electron configuration of the isotropic field. Meanwhile, crystal field splitting energy refers to the energy difference between d orbitals of the ligands.

The terms crystal field stabilization energy and splitting energy come under the crystal field theory. The crystal field theory or CFT is a chemical concept which describes the breakdown of the degeneracies of the electron orbitals due to a charge distribution in the surrounding. This theory is very useful in explaining the properties of transition metal complexes.

CONTENTS

1. Overview and Key Difference
2. What is Crystal Field Stabilization Energy 
3. What is Crystal Field Splitting Energy
4. Side by Side Comparison – Crystal Field Stabilization Energy vs Splitting Energy in Tabular Form
5. Summary

What is Crystal Field Stabilization Energy?

Crystal field stabilization energy or CFSE refers to the energy difference between the energy of the electron configuration of the ligand and the energy of electron configuration of the isotropic field. When a ligand comes closer to the metal centre, there is a repulsion between the electrons of the ligand and the electrons of the metal atom. As a consequence, the d orbitals of the metal atom tends to split into two sets when the ligand approaches the metal atom. The two sets of orbital levels are named e_g and t_2g. The energy difference between these two energy level sets is equal to the crystal field stabilization energy. So, this energy value explains the strength of the repulsive force between electrons of the ligand and the electrons of the metal atom.

There are a few factors that can affect the crystal field stabilization energy:

1. Nature of the ligand
2. Nature of the central metal atom
3. Geometry of coordination complex
4. Quantum number of the central metal atom

What is Crystal Field Splitting Energy?

Crystal field splitting energy refers to the energy difference between d orbitals of the ligands. Another name for this term is ligand field splitting energy. We use the Greek letter Δ to denote crystal field splitting.

In crystal field splitting, the d orbitals of the central metal atom tend to split into two or more energy levels to allow the ligands to bind with the metal atom via coordinate bonding. The energy difference between the d orbital splitting levels is called the crystal field splitting energy.

What is the Difference Between Crystal Field Stabilization Energy and Splitting Energy?

The terms crystal field stabilization energy and splitting energy fall under the crystal field theory. The key difference between crystal field stabilization and splitting energy is that crystal field stabilization energy refers to the energy difference between the energy of the electron configuration of the ligand and the energy of electron configuration of isotropic field. But, the crystal field splitting energy refers to the energy difference between d orbitals of the ligands.

Below infographic summarizes the difference between crystal field stabilization and splitting energy.

Summary – Crystal Field Stabilization Energy vs Splitting Energy

The terms crystal field stabilization energy and splitting energy fall under the crystal field theory. The key difference between crystal field stabilization and splitting energy is that the crystal field stabilization energy refers to the energy difference between the energy of the electron configuration of the ligand and isotropic field. But, crystal field splitting energy refers to the energy difference between d orbitals of the ligands.

Reference:

1. “Crystal Field Stabilization Energy.” Chemistry LibreTexts, Libretexts, 5 June 2019, Available here.
2. Khalid, Amna. “Crystal Field Stabilization Energy.” LinkedIn SlideShare, 11 Mar. 2018, Available here.
3. “Crystal-Field Splitting Energy.” Encyclopædia Britannica, Encyclopædia Britannica, Inc., Available here.
4. Helmenstine, Anne Marie. “Crystal Field Splitting Definition.” ThoughtCo, Mar. 28, 2019, Available here.

Image Courtesy:

1. “Octahedral crystal-field splitting” By English Wikipedia user YanA (CC BY-SA 3.0) via Commons Wikimedia
2. “Square antiprismatic” By The original uploader was YanA at English Wikipedia.(Original text: YanA) – Own work (Original text: self-made) (CC BY-SA 3.0) via Commons Wikimedia