What is the approximate Emax value for octahedral complexes?

In the context of octahedral complexes, Emax refers to the energy separation between the split d-orbitals due to ligand field splitting, often represented by the parameter Δoct. For octahedral complexes, Δoct values can range significantly depending on the metal ion and the ligands coordinated to it. However, typical values for Δoct often fall within the range of 200 to 1000 cm⁻¹ for common transition metal complexes.

The approximate value for Δoct in many octahedral complexes can typically be in the order of 100 to 300 cm⁻¹, depending on the ligand's strength (for example, weak field versus strong field ligands). Given that the commonly referenced energy separations used in educational contexts for many transition metal complexes generally center around figures in the lower end of this range, the approximation of 100 cm⁻¹ is a reasonable value associated with weaker field ligands in octahedral coordination.

It's worth noting that much higher values can also occur with strong field ligands or specific metal-ligand combinations, but for this question and the standard contexts of octahedral coordination chemistry, 100 cm⁻¹ is a commonly used approximation for Emax.