Draw a diagram to show how the $\mathrm{d}-$orbitals split into groups with different energy in an octahedral ligand field. Some electronic configurations may exist in both high spin and low spin arrangements in an octahedral field. Draw all of these cases and suggest which metal ions and ligands give rise to each.

Draw the energy level diagrams and indicate the occupancy of the orbitals in the following complexes.

(a) ${\mathrm{d}}^6$, octahedral, low spin
(b) ${\mathrm{d}}^{\text{9}}$, octahedral with tetragonal elongation
(c) ${\mathrm{d}}^8$, square planar
(d) ${\mathrm{d}}^6$, tetrahedral

Calculate the difference in crystal field stabilization energy (in unit of ${\mathrm{\Delta }}_{\mathrm{o}}$) between the complexes (a) and (d), assuming that the ligands are strong field ligands.

(Answer: octahedral $-2.4 {\mathrm{\Delta }}_{\mathrm{o}}$, tetrahedral $-0.27 {\mathrm{\Delta }}_{\mathrm{o}}$, difference $-2.13 {\mathrm{\Delta }}_{\mathrm{o}}$)