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The Basics of Covalent Bonding in Terms of Energy and Dynamics

We address the paradoxical fact that the concept of a covalent bond, a cornerstone of chemistry which is well resolved computationally by the methods of quantum chemistry, is still the subject of debate, disagreement, and ignorance with respect to its physical origin. Our aim here is to unify two se...

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Autores principales: Nordholm, Sture, Bacskay, George B.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7321125/
https://www.ncbi.nlm.nih.gov/pubmed/32521828
http://dx.doi.org/10.3390/molecules25112667
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author Nordholm, Sture
Bacskay, George B.
author_facet Nordholm, Sture
Bacskay, George B.
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description We address the paradoxical fact that the concept of a covalent bond, a cornerstone of chemistry which is well resolved computationally by the methods of quantum chemistry, is still the subject of debate, disagreement, and ignorance with respect to its physical origin. Our aim here is to unify two seemingly different explanations: one in terms of energy, the other dynamics. We summarize the mechanistic bonding models and the debate over the last 100 years, with specific applications to the simplest molecules: H(2)(+) and H(2). In particular, we focus on the bonding analysis of Hellmann (1933) that was brought into modern form by Ruedenberg (from 1962 on). We and many others have helped verify the validity of the Hellmann–Ruedenberg proposal that a decrease in kinetic energy associated with interatomic delocalization of electron motion is the key to covalent bonding but contrary views, confusion or lack of understanding still abound. In order to resolve this impasse we show that quantum mechanics affords us a complementary dynamical perspective on the bonding mechanism, which agrees with that of Hellmann and Ruedenberg, while providing a direct and unifying view of atomic reactivity, molecule formation and the basic role of the kinetic energy, as well as the important but secondary role of electrostatics, in covalent bonding.
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spelling pubmed-73211252020-07-06 The Basics of Covalent Bonding in Terms of Energy and Dynamics Nordholm, Sture Bacskay, George B. Molecules Review We address the paradoxical fact that the concept of a covalent bond, a cornerstone of chemistry which is well resolved computationally by the methods of quantum chemistry, is still the subject of debate, disagreement, and ignorance with respect to its physical origin. Our aim here is to unify two seemingly different explanations: one in terms of energy, the other dynamics. We summarize the mechanistic bonding models and the debate over the last 100 years, with specific applications to the simplest molecules: H(2)(+) and H(2). In particular, we focus on the bonding analysis of Hellmann (1933) that was brought into modern form by Ruedenberg (from 1962 on). We and many others have helped verify the validity of the Hellmann–Ruedenberg proposal that a decrease in kinetic energy associated with interatomic delocalization of electron motion is the key to covalent bonding but contrary views, confusion or lack of understanding still abound. In order to resolve this impasse we show that quantum mechanics affords us a complementary dynamical perspective on the bonding mechanism, which agrees with that of Hellmann and Ruedenberg, while providing a direct and unifying view of atomic reactivity, molecule formation and the basic role of the kinetic energy, as well as the important but secondary role of electrostatics, in covalent bonding. MDPI 2020-06-08 /pmc/articles/PMC7321125/ /pubmed/32521828 http://dx.doi.org/10.3390/molecules25112667 Text en © 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Review
Nordholm, Sture
Bacskay, George B.
The Basics of Covalent Bonding in Terms of Energy and Dynamics
title The Basics of Covalent Bonding in Terms of Energy and Dynamics
title_full The Basics of Covalent Bonding in Terms of Energy and Dynamics
title_fullStr The Basics of Covalent Bonding in Terms of Energy and Dynamics
title_full_unstemmed The Basics of Covalent Bonding in Terms of Energy and Dynamics
title_short The Basics of Covalent Bonding in Terms of Energy and Dynamics
title_sort basics of covalent bonding in terms of energy and dynamics
topic Review
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7321125/
https://www.ncbi.nlm.nih.gov/pubmed/32521828
http://dx.doi.org/10.3390/molecules25112667
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