D orbitals vs Regular Orbitals

[raina_bandekar_1G]

Can someone explain how D orbitals act differently in the context of crystal field theory? Why are these orbitals special?

[006248274]

D-orbitals have 5 orbitals that each can fit 2 electrons, at different energy levels. When bonded to ligands, these d-orbitals can degenerate their energies even more and they split their 5 D oribitals into 3 at a lower level and 2 at a higher level. An electron can then be promoted to a higher energy level and emit color. That can only happen with UNFILLED d orbitals(very important that theyre unfilled)