1. Chapter 3 Notes: Colored complexes
Chapter 13.2: d orbitals have the same energy in an isolated atom, but split into two sub-levels in a complex ion. The electric field of ligands cause the d orbitals in complex ions to split so that the energy of an electron transition between them corresponds to a photon of visible light.
Chapter 3 Notes: Colored complexes

2. Important terms for this section
Colored complexes
Nuclear charge
Charge density
Oxidation state

4. The color absorbed means the complementary color is reflected (so you will see it)
If copper chloride is cyan (blue-green), then red-orange is being absorbed

5. Why do TM absorb light?
In a TM complex, d-sublevel splits when an electric field (or light) is applied
One of the 3d electrons is excited to a higher sub-level
Note: Not same as e- emitting
photon when return to
ground state

7. Color depends on… The difference in energy between the split sublevels
The nuclear charge
Identity of central metal ion
Charge and density of ligand
Geometry of complex ion
Oxidation number of central metal ion (number of d electrons)

8. Nuclear charge and ID of metal
Higher nuclear charge
More strongly interacting with its ligands
Therefore, absorbs light with higher energy
Ex: [Mn(H2O)6]2+ vs [Fe(H2O)6]3+
Mn = lower ENC  absorbs green  show pink
Fe = higher ENC  absorbs blue  show orange

9. Charge density of the ligand
Charge density: density of charge around the ion
Greater the charge density of the ligand
Greater the split of the d orbitals
Absorbs higher energy light
Spectrochemical series of ligands: separates ligands by energy separation of d orbitals
Spectrochemical series is in Section 15 of data booklet

11. Number d electrons and oxidation state of central metal ion
Oxidation state of metal depends on no. of d e-
More e- means more repulsion of ligand
This means less interaction of metal with ligand
If oxidation number is higher = ligand repulsed by d e- and greater splitting of d orbitals
Vanadium oxidation state ions 