Chemical Bonding 2: Modern Theories of Chemical Bonding

Orbital Theory ◽

Valence Bond Theory ◽

Electron Group ◽

Bond Theory ◽

Lewis Structures

Chemical Bonding II: Modern Theories of Chemical Bonding explains four bonding theories related to molecular geometry and bonding. Lewis structures and the Valence-Shell Electron-Pair Repulsion (VSEPR) model are used to describe and predict the electron group geometry, molecular geometry and shapes of molecules. The VSEPR model is then used to predict molecular polarity as a function of shape. This leads to Valence Bond Theory, which uses the principles of orbital overlap and hybridization of atomic orbitals to describe chemical bonding. Finally the Molecular Orbital Theory (MOT) based on electron delocalization is discussed in terms of bonding and anti-bonding molecular orbitals.

A Brief Story of Valence Bond Theory, Its Rivalry with Molecular Orbital Theory, Its Demise, and Resurgence

A Chemist's Guide to Valence Bond Theory ◽

10.1002/9780470192597.ch1 ◽

2007 ◽

pp. 1-25 ◽

Cited By ~ 1

Keyword(s):

Molecular Orbital ◽

Valence Bond ◽

Orbital Theory ◽

Valence Bond Theory ◽

Computational Materials, Chemistry, and Biochemistry: From Bold Initiatives to the Last Mile - Springer Series in Materials Science ◽

Beyond Molecular Orbital Theory: The Impact of Generalized Valence Bond Theory in Molecular Science

10.1007/978-3-030-18778-1_5 ◽

2021 ◽

pp. 55-87

Author(s):

Thom H. Dunning ◽

P. Jeffrey Hay

Keyword(s):

Molecular Orbital ◽

Valence Bond ◽

Orbital Theory ◽

Valence Bond Theory ◽

Generalized Valence Bond ◽

Bond Theory ◽

Generalized Valence Bond Theory ◽

The Impact ◽

Molecular Science

Relative validity of the valence bond theory and of the molecular orbital theory for description of conjugated hydrocarbons

Molecular Physics ◽

10.1080/00268976600100981 ◽

1966 ◽

Vol 11 (2) ◽

pp. 153-159 ◽

Cited By ~ 2

Author(s):

H. Looyenga

Keyword(s):

Molecular Orbital ◽

Valence Bond ◽

Orbital Theory ◽

Relative Validity ◽

Valence Bond Theory ◽

Conjugated Hydrocarbons ◽

Valence Bond Theory—Its Birth, Struggles with Molecular Orbital Theory, Its Present State and Future Prospects

Molecules ◽

10.3390/molecules26061624 ◽

2021 ◽

Vol 26 (6) ◽

pp. 1624

Author(s):

Sason Shaik ◽

David Danovich ◽

Philippe C. Hiberty

Keyword(s):

Molecular Orbital ◽

Present State ◽

Valence Bond ◽

Future Prospects ◽

Orbital Theory ◽

Linus Pauling ◽

Valence Bond Theory ◽

Bond Theory ◽

Mo Theory

This essay describes the successive births of valence bond (VB) theory during 1916–1931. The alternative molecular orbital (MO) theory was born in the late 1920s. The presence of two seemingly different descriptions of molecules by the two theories led to struggles between the main proponents, Linus Pauling and Robert Mulliken, and their supporters. Until the 1950s, VB theory was dominant, and then it was eclipsed by MO theory. The struggles will be discussed, as well as the new dawn of VB theory, and its future.

Proceedings of the Royal Society of London Series A - Mathematical and Physical Sciences ◽

Electronic levels in simple conjugated systems, I. Configuration interaction in cyclobutadiene

10.1098/rspa.1950.0115 ◽

1950 ◽

Vol 202 (1071) ◽

pp. 498-506 ◽

Cited By ~ 28

Keyword(s):

Molecular Orbital ◽

Configuration Interaction ◽

Energy Levels ◽

Valence Bond ◽

Wave Functions ◽

The Other ◽

Orbital Theory ◽

Valence Bond Theory ◽

Symmetry Properties ◽

In the simplest cyclic system of π-electrons, cyclobutadiene, a non-empirical calculation has been made of the effects of configuration interaction within a complete basis of antisymmetric molecular orbital configurations. The molecular orbitals are made up from atomic wave functions and all the interelectron repulsion integrals which arise are included, although those of them which are three- and four-centre integrals are only known approximately. In this system configuration interaction is a large effect with a strongly differential action between states of different symmetry properties. Thus the 1 A 1g state is several electron-volts lower than the lowest configuration of that symmetry, whereas for 1 B 1g the comparable figure is about one-tenth of an electron-volt. The other two states examined, 1 B 2g and 3 A 2g are affected by intermediate amounts. The result is a drastic change in the energy-level scheme compared with that based on configuration wave functions. Neither the valence-bond theory nor the molecular orbital theory (in which the four states have the same energy) gives a satisfactory account of the energy levels according to these results. One conclusion from the valence-bond theory which is, however, confirmed, is the somewhat unexpected one that the non-totally symmetrical 1 B 2g state is more stable than the totally symmetrical 1 A 1g . On the other hand, it is clear that the valence-bond theory, with the usual value for its exchange integral, grossly exaggerates the resonance splitting of the states, giving separations between them several times too great. Thus the valence-bond theory leads to large values of the resonance energy (larger, per π-electron, than in benzene) and so associates with the molecule a considerable π-electron stabilization. This expectation has no support in the present more detailed and non-empirical calculations.

Proceedings of the Royal Society of London Series A - Mathematical and Physical Sciences ◽

The molecular orbital theory of chemical valency XIII. Orbital wave functions for excited states of a homonuclear diatomic molecule

10.1098/rspa.1953.0031 ◽

1953 ◽

Vol 216 (1126) ◽

pp. 424-433 ◽

Cited By ~ 3

Keyword(s):

Molecular Orbital ◽

Excited States ◽

Valence Bond ◽

Present Theory ◽

Wave Functions ◽

Orbital Theory ◽

Bond Theory ◽

Homonuclear Diatomic Molecules ◽

Approximate Wave

The expansions for the exact wave functions for excited states of homonuclear diatomic molecules derived in part XII are used as the basis for discussing various approximate wave functions of the orbital type. The states considered in detail are the lowest states of symmetries 1 Σ u + , 3 Σ u + . The calculus of variations is used to determine the optimum forms for the component orbital functions. A transformation to equivalent orbitals is used to bring out the physical significance of the various wave functions, and to relate the present theory to earlier theories, in particular the molecular orbital theory, the valence-bond theory and their generalizations.

1. Matter from the inside

Physical Chemistry: A Very Short Introduction ◽

10.1093/actrade/9780199689095.003.0001 ◽

2014 ◽

pp. 1-21

Author(s):

Peter Atkins

Keyword(s):

Quantum Mechanics ◽

General Structure ◽

Valence Bond ◽

Pauli Exclusion Principle ◽

Exclusion Principle ◽

Orbital Theory ◽

Covalent Bonds ◽

‘Matter from the inside’ shows that one way to understand how a physical chemist thinks and contributes to chemistry is to start at the atom's interior and then travel out into the world of bulk matter. It begins with the electronic structure of atoms, introduces the role of quantum mechanics in accounting for electron arrangement, and outlines Schrödinger's model of s-, p-, d-, and f-orbitals and the Pauli exclusion principle. Physical chemistry accounts for the general structure of the Periodic Table. The radius, ionization energy, and electron affinity properties of atoms are then considered along with ionic and covalent bonds, and the quantum mechanics of bonds, including valence-bond theory and molecular orbital theory.