Compare and contrast the MO model with the LE model. When is each useful?

The Molecular Orbital (MO) model is a quantum mechanical model that describes electron distribution in molecules by considering the overlap of atomic orbitals to form delocalized molecular orbitals. It is useful for understanding chemical bonding, orbital energies, charge distribution, and magnetic and spectroscopic properties of molecules. The Ligand Field (LE) model, an extension of Crystal Field Theory, focuses on the effect of the electric field created by ligands on the splitting of a metal ion's d-orbitals into non-degenerate energy levels. It is useful for understanding electronic structures of coordination complexes, colors exhibited, structural and magnetic properties, and stability or reactivity of complexes. Both models can be applied to transition-metal complexes, but the MO model is generally more accurate for highly covalent cases and charge transfer transitions, while the LE model offers a simpler way to understand electronic structures and energy levels. The choice of the model depends on the level of detail desired.