Which theories go beyond the crystal field model to address its weaknesses, such as the covalent nature of bonding and the discrepancies in ligand splitting effects?

To address the limitations of the crystal field model (CFT), more advanced theories like ligand field theory (LFT) and molecular orbital theory (MO theory) have been developed. Ligand field theory extends CFT by incorporating covalent bonding aspects, considering the overlap of metal and ligand orbitals. Molecular orbital theory provides a more comprehensive understanding by treating metal-ligand interactions as molecular orbitals formed from both metal and ligand atomic orbitals. These theories offer a more nuanced perspective on the electronic structure and bonding in coordination compounds, going beyond the simplified electrostatic approach of the crystal field model.