* Crystal Field Theory
- the colors and magnetic properties of metal complexes are related to the d-orbitals
they possess
- crystal field theory attempts to explain these phenomena thru electrostatic
interactions
- octahedral complexes
-- recall what an octahedral looks like and the shapes of the d-orbitals
-- we know the bond between the metal center and a ligand occurs thru the
donation of a lone pair (lp) of the ligand donor atom to the central metal
-- if we think of this lp approaching the d-orbitals along the corner points of
the octahedral there will be more repulsion btwn the lp and the
d-orbital that is pointing toward one of these corners
-- the 5 d-orbitals no longer have the same energy - the d_x2-y2 and d_z2
orbitals are higher in energy than the d_xy, d_xz, and d_yz due to the
increased repulsive energy
-- the difference in energy btwn the two sets of orbitals is the crystal field
splitting energy, โ0 = hc/ฮป where h = 6.63 x 10-34 Js and
c = 3.00 x 108 m/s
- back to color - e.g. [Ti(H2O)5]3+ (500 nm)
-- โE = โ0 therefore the absorption energy is the amount of energy needed to
overcome the crystal field so to speak
-- this is the relationship btwn CFT and the complex color
- high spin vs. low spin
-- recall that when we ionize a transition metal the first e-'s to go are the 4s
not the 3d
-- we call the metallic ion a dn - e.g. Fe3+ is a d5 because it has 5 e-'s in the
