What factor determines whether the crystal field in an octahedral complex is to be regarded as strong or weak? How many d-electrons must be present in orbitals of the central atom atom for there to be an abrupt change in crystal field stabilisation energy strong and weak fields gt

Explanation

To determine whether the crystal field in an octahedral complex is regarded as strong or weak, we need to consider the following factors:

### Step-by-Step Solution:

1. **Understanding Crystal Field Theory (CFT)**:
- Crystal Field Theory explains how the arrangement of ligands around a central metal ion affects the energy levels of the d-orbitals. In an octahedral complex, the d-orbitals split into two sets: the lower energy \( t_{2g} \) orbitals and the higher energy \( e_g \) orbitals.

**Hint**: Remember that the splitting of d-orbitals is influenced by the nature of the ligands surrounding the metal ion.
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