What is the approximate Emax value for square planar complexes?

The Emax value for square planar complexes typically refers to the energy separation between the lowest energy d-orbitals involved in the electronic transitions of metal complexes, particularly in transition metal complexes. In square planar geometry, these complexes generally exhibit significant splitting of their d-orbitals due to the influence of the ligand field.

In a square planar complex, the d-orbitals are split into different energy levels, and the two orbitals that are most highly influenced by the ligand field (dxy and dx2-y2) typically experience the largest energy difference. This results in a higher Emax value compared to other geometric configurations like tetrahedral or octahedral complexes, where the d-orbital splitting is less pronounced.

The approximate Emax value of around 100 for square planar complexes is consistent with observed spectroscopic data, indicating that the ligands in this geometry create a strong field environment that leads to significant d-orbital splitting. Therefore, the choice reflecting an Emax value of 100 aligns with this understanding of square planar coordination complexes and their electronic properties.