Name: Nomenclature of Coordination Compounds - I
Uploaded: 2019-07-19
Duration: 7 min 4 s
Description: All the chemical compounds are assigned a name, which is done according to a specific rule. How are coordination compounds named? Let’s watch the video to fi...

Question

Write the assumptions of crystal field theory. Discuss the pattern of splitting of

d

-orbitals under the effect of an octahedral crystal field.

Accepted Answer

Crystal field theory considers the metal-ligand bond to be ionically arising from electrostatic interactions between the central metal ion and the ligand, and these ligands are treated as point charges. In the case of a negative ligand, the interactions with the metal ions are ion-ion interactions, and if the ligand is neutral, the interaction with metal ion are ion-dipole interaction. In the case of free metal ions, all the five $d$ -orbital possess the same energy, and the orbitals having the same energy are called degenerate orbitals. But in the presence of ligands, the orbital's electrons are repelled by the electron pairs of ligands resulting in to arise in the energy of the $d$ -orbitals, and these orbitals have different orientations, therefore, these orbitals will experience different interactions from the ligands.

(I) The orbitals which are lying in the direction of the ligands experience greater repulsion and their energies will be raised to their position in the symmetric field.

(II) The orbitals which are away from the approach of ligands will have lesser interaction, therefore, their energies will be lowered.

Due to the electrical field of the ligands, these five degenerate orbitals split up.

Splitting of $d$ -orbitals under the effect of an octahedral ligand- The crystal field splitting depends on the nature of ligands. The greater the ease with which the ligand can approach the metal ion, the greater the crystal field splitting caused by it.

In an octahedral complex, the metal ion is at the centre of the octahedron, and all the six ligands represented as point charges lie at the six corners along the three axes. In the octahedral complexes, all the five $d$ -orbital do not possess the same energy, they split up due to the interaction of the ligands. On the basis of the shape of $d$ -orbitals in the octahedral complex, the orbitals $d_{z^{2}}$ and $d_{x^{2} - y^{2}}$ lie on the axis means that the lobes are in the direction towards ligands while the lobes of $d_{xy,} d_{yz}$ and $d_{xz}$ are between the points charges or between the axis. Therefore, the three orbitals $d_{xy,} d_{yz}$ and $d_{xz}$ experience less repulsion and are stable while the two orbitals $d_{z^{2}}$ and $d_{x^{2} - y^{2}}$ experience more repulsion and possess more energy.

Write the assumptions of crystal field theory. Discuss the pattern of splitting of $d$ -orbitals under the effect of an octahedral crystal field.

Important Questions on Co-Ordination Compounds

Learn and Prepare for any exam you want !

Write the assumptions of crystal field theory. Discuss the pattern of splitting of d-orbitals under the effect of an octahedral crystal field.

Important Questions on Co-Ordination Compounds

Learn and Prepare for any exam you want !

Write the assumptions of crystal field theory. Discuss the pattern of splitting of $d$ -orbitals under the effect of an octahedral crystal field.