The ionic radii for metal–ligand complexes that are in an octahedral coordination are easy to find. I understand that when the $\mathrm{e_g}$ orbital is filled, the ionic radius increases because the electrons repel the ligands meaning the ionic radius increases.
But I am not sure about tetrahedrally coordinated metal–ligand complexes. I think it might be the same for the first two to three electrons, but since the $\mathrm{t_{2g}}$ orbital electrons are degenerate, the $Z_\mathrm{eff}$ might be stronger “felt” by the ligands.
