According to Crystal Field Theory, what is the crystal field splitting energy for an octahedral complex?

Solution

1. In an octahedral field, the five degenerate d-orbitals split into two sets.
2. The lower energy set consists of three $t_{2g}$ orbitals ($d_{xy},d_{yz},d_{zx}$).
3. The higher energy set consists of two $e_g$ orbitals ($d_{x^2-y^2},d_{z^2}$).
4. The energy difference between these two sets is defined as the crystal field splitting energy, denoted as ${\Delta }_o$.
5. Hence the answer is (A).