Molecules and Models

Abstract

The book opens with three chapters describing the properties of atoms. The first chapter deals with the application of quantum mechanics to hydrogen and other one-electron atoms; the second with the use of the atomic orbital model to describe He and other two-electron atoms; the third gives an overview of the electron configurations, ground state energies, ionization energies, electronegativity coefficients, and atomic sizes of poly-electron atoms. The following six chapters deal with the properties of diatomic molecules, in particular their bond distances, dissociation energies, electric dipole moments, and estimated net atomic charges. The molecular structures of compounds of the elements in Groups 2 and 12, and in Groups 13 through 18 are described in separate chapters, with particular emphasis on hydrogen, methyl, and halogen derivatives. The main emphasis is on equilibrium structures, but bond energies are included in the discussion whenever available, and large amplitude motion like the inversion of amines, pseudorotation in five-coordinate species, or intermolecular rearrangements through rapid dissociation and recombination are discussed. The structures of electron deficient molecules and of electron donor-acceptor complexes are described in separate chapters. The final chapter discusses the structures and bonding in oxides and oxoacids of carbon, sulfur, nitrogen phosphorus, and chlorine. Throughout the book, models concepts like the spherical ion model, the electron pair bond, Lewis structures, atomic bonding radii, the valence shell electron pair repulsion (VSEPR) model, or the molecular orbital model are introduced as the need arises. Attention is paid to both the successes and failures of each model.