After much heated discussion on a hazy Wednesday afternoon at North Spine MacDonald,our two Chemistry gods, Nathanal Wong and Kang Jing have suggested that we should approach this question by looking at how the ligands approach the central metal ion. The other 3 immortals namely Sophia, Amber and me, Alenson, agreed unanimously. The axis in which the ligands approach will encounter greater electrostatic forces of repulsion between the electrons in the respective d orbital of the metal ion and the lone pair on the ligands. As a result, those d- orbital which bisects the angle of approach will encounter greater electrostatic forces of attraction and will be of higher energy level than d-orbitals which are perpendicular to the angle of approach.
For example in the case of linear geometry where the electrons approach from 1 and 6, which is the z axis, dz2 orbitals encounter greatest electrostatic forces of attraction and hence has the highest energy level since the ligands approach directly at the z axis, in which the dz2 lies on.
The same applies for dxz and dyz orbital. However, unlike dz2 orbitals, these two orbitals do not lie entirely on the z-axis, but only partially on the z plane. Hence they will encounter lesser electrostatic forces of repulsion than dz2 but greater than dxy and d x2-y2 orbitals which are perpendicular away from the z axis.
That’s all folks =) Have a great week ahead!
Love Chemistry!
