Explanation:
The distortion in octahedral complexes occurs due to the Jahn-Teller effect, which arises from the interaction between the electronic and vibrational states of a molecule or ion. The Jahn-Teller effect leads to a distortion in the geometry of the complex, resulting in a non-spherical shape.

Distortion in Octahedral Complexes:
The degree of distortion in octahedral complexes depends on the d-electron configuration of the metal ion. In general, complexes with a d5 or d6 electron configuration exhibit greater distortion than those with other electron configurations.

d5 High Spin:
In d5 high spin complexes, the five electrons occupy the t2g orbitals, while the eg orbitals remain empty. Since the electrons are all paired, there is no net magnetic moment, and the complex is diamagnetic. The lack of unpaired electrons means that the complex is less susceptible to the Jahn-Teller effect and, therefore, exhibits less distortion.

d5 Low Spin:
In d5 low spin complexes, the five electrons occupy the t2g orbitals and the eg orbitals. The electrons in the eg orbitals are paired, while one electron occupies each of the three t2g orbitals. The complex is paramagnetic, and the unpaired electrons make it more susceptible to the Jahn-Teller effect. This leads to a greater degree of distortion in d5 low spin complexes than in d5 high spin complexes.

d6 High Spin:
In d6 high spin complexes, the six electrons occupy the t2g and eg orbitals, with two electrons in each of the three orbitals. The complex is diamagnetic, and the lack of unpaired electrons means that it is less susceptible to the Jahn-Teller effect. Therefore, d6 high spin complexes exhibit less distortion.

d6 Low Spin:
In d6 low spin complexes, the six electrons occupy the t2g orbitals, and there are no electrons in the eg orbitals. The complex is diamagnetic, and the lack of unpaired electrons means that it is less susceptible to the Jahn-Teller effect. Therefore, d6 low spin complexes exhibit less distortion.

Conclusion:
In summary, the degree of distortion in octahedral complexes depends on the d-electron configuration of the metal ion. In general, d5 and d6 complexes exhibit greater distortion than those with other electron configurations. Within d5 and d6 complexes, low spin complexes exhibit greater distortion than high spin complexes.