Question

The splitting of degenerated d-orbitals takes place into which of the following two sets :

• A. $d_{xy},d_{z^2},d_{xz}$and $d_{yz},d_{x^2-y^2}$
• B. $d_{xy},d_{yz},d_{zx}$ and $d_{x^2-y^2},d_{z^2}$
• C. $d_{xy},d_{x^2-y^2},d_{z^2}$ and $d_{yz},d_{xz}$
• D. $d_{xy},d_{x^2-y^2},d_{xz}$ and $d_{yz},d_{z^2}$

Answer 1

Answer: (B)

$d_{xy},d_{yz},d_{zx}$ and $d_{x^2-y^2},d_{z^2}$

The d-orbitals split into two sets with an energy difference, the crystal-field splitting parameter where the $d_{xy},d_{xz}and{d}_{yz}$ orbitals will be lower in energy than the $d_{z^2}and{d}_{x^2-y^2}$, which will have higher energy, because the former group is farther from the ligands than the latter and therefore experience less repulsion. The three lower-energy orbitals are collectively referred to as $t_{2g}$, and the two higher-energy orbitals as $e_g$.