In the splitting of -orbitals in a purely octahedral crystal field, which of the specific orbitals c — Coordination Compounds Chemistry Question
Question
In the splitting of $d$ -orbitals in a purely octahedral crystal field, which of the specific orbitals constitute the doubly degenerate $e_g$ set that is raised in energy?
💡 Solution & Explanation
In an octahedral complex, the ligands approach the central metal ion directly along the Cartesian axes (x, y, and z). The $d$ -orbitals that possess electron density concentrated exactly along these axes will experience the maximum electrostatic repulsion from the ligands. These are the $d_{x^2-y^2}$ and $d_{z^2}$ orbitals, which are collectively termed the $e_g$ set and are raised in energy. The non-axial orbitals ($d_{xy}$, $d_{yz}$, $d_{zx}$) become the $t_{2g}$ set.