To my understanding, Crystal Field Theory allows for an explanation for the colors of transition metal complex ions due to the d-d transitions which occur. This transition ∆o, is from the t2g orbitals to the eg.

Now looking at Ligand Field Theory. Is it right to say that this is equivalent to/same as the transition from the t2g orbitals to the eg* or t2g* to eg* orbitals depicted in the diagrams below?

MO Diagrams For Octahedral Complexes


(Assuming octahedral complex with sigma bonding only)

Moreover, I was also initially confused due to the issue that if two of the d-orbitals of the transition metal ion is used for bonding with ligands e.g in a hexaaquachromium(III), [Cr(H20)6]3+, how would the d-d transitions occur if these eg orbitals are involved in sigma bonding with 6 of the ligands.

Is it right to say that the d-d transitions occur from the t2g non-bonding orbitals to the eg* anti-bonding orbitals and that the bonding with the ligands involve eg bonding orbitals which is separate to the anti-bonding eg orbitals?

In summary, I have the impression that CFT provides an explanation for the colors of complex ions and LFT provides an explanation for the bonding of transition metal ions with ligands as well as the colors. Hence, is that fact that there are bonding and anti bonding orbitals which allows for the both the colors and the bonding with ligands?

MO diagrams for octahedral complexes


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