Chemical Bonding in Transition Metal Compounds

This chapter deals with the nature of the chemical bonding in transition metal compounds. The difference between spn-hybridized orbitals of main group atoms and sdn hybridized orbitals of transition metals is discussed. The principle shapes of sdn hybrid orbitals and the influence of π interaction on the geometry of transition metal compounds are elucidated. It is shown that the qualitative bonding model of Dewar, Chatt, and Duncanson (DCD) is supported by a quantitative energy decomposition analysis (EDA), which provides a bridge between accurate chemical calculations and heuristically derived concepts. Transition metal-ligand bonding in various classes of complexes, which are representative for transition metal chemistry, is investigated. It is shown that quantum chemical methods do not only provide reliable numerical results but also can also be used to derive insight into the nature of the bonding, which is very useful for the understanding and the interpretation of experimental results.