Lewis-like Structures: Robustness of Lewis-like Concepts and Bonding Across the Periodic Table
Clark Landis
Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin, USA.
Mercredi 8 Octobre 2014, 11h00
bibliothèque LCT, tour 12 - 13, 4e étage
Are Lewis structures consistent with high quality electronic structures? Natural Bond Orbital (NBO) analysis of molecules across the periodic table supports the primacy of Lewis-like structures in many small molecules. Deviations from Lewis-like structures are described by consistent and logical donor-acceptor concepts. Key to judging the validity of Lewis-like structures is the difference between the ab initio one-electron density matrix and that of the idealized Lewis structure. This metric-of-quality reveals that many concepts - Lewis structures, hybridization, electronegativity, resonance, etc. - originating from pre- and early quantum days, not only survive scrutiny but form the basis for new insights into the electronic structures of transition metal, and other, molecules. Featured examples include hypervalency and "long-bond" motifs, open shell molecules and the Different Lewis Structures for Different Spins (DLDS) paradigm, applications to transition metal complexes, and insights provided by the NBO facilities for deletion of Fock matrix elements as expressed in the NBO basis set.