I am trying to understand how complexes are coloured. After some reading, I found out this was due to the d-d splitting induced by the co-ordinate bonds of ligands to the central metal ion. The electrons in the d orbitals then transition between each other, and absorb light in the process.

However, I do not understand what happens to the electrons donated by the ligand. Don't they form a sigma bond with the d-orbitals of the metal ion? In which case, wouldn't they go into the d-orbitals and 'fill it up', thus disallowing transitions?

Or is it the case that the d-orbitals of the central metal ion do not involve in the bonding at all?

I am trying to understand how complexes are coloured. After some reading, I found out this was due to the d-d splitting induced by the coordinate bonds of ligands to the central metal ion. The electrons in the d-orbitals then transition between each other, and absorb light in the process.

However, I do not understand what happens to the electrons donated by the ligand. Don't they form a sigma bond with the d-orbitals of the metal ion? In which case, wouldn't they go into the d-orbitals and 'fill it up', thus disallowing transitions?

Or is it the case that the d-orbitals of the central metal ion are not involved in the bonding at all?

I am trying to understand how complexes are coloured. After some reading, I found out this was due to the d-d splitting induced by the co-ordinate bonds of ligands to the central metal ion. The electrons in the d orbitals then transition between each other, and absorb light in the process.

However, I do not understand what happens to the electrons donated by the ligand. Don't they form a sigma bond with the d-orbitals of the metal ion? In which case, wouldn't they go into the d-orbitals and 'fill it up', thus disallowing transitions?

Or is it the case that the d-orbitals of the central metal ion do not involve in the bonding at all? Thanks in advance for your help.

I am trying to understand how complexes are coloured. After some reading, I found out this was due to the d-d splitting induced by the co-ordinate bonds of ligands to the central metal ion. The electrons in the d orbitals then transition between each other, and absorb light in the process.

However, I do not understand what happens to the electrons donated by the ligand. Don't they form a sigma bond with the d-orbitals of the metal ion? In which case, wouldn't they go into the d-orbitals and 'fill it up', thus disallowing transitions?

Or is it the case that the d-orbitals of the central metal ion do not involve in the bonding at all?