Bonding as a Problem in Classical Electrostatics

The chief content of the isomorphism displayed in Table 1 is embodied in the phrase electride ion . By introducing at the outset in the electronic interpretation of chemistry the wave-like character of electrons and the Exclusion Principle through the concept of van der Waals-like electron-domains or electride ions , whose sizes indicate the magnitudes of the electrons kinetic energies, whose impenetrability8) simulates, at least approximately, the operation of the Exclusion Principle, and whose charges yield within the framework of the model easily foreseeable effects, one transforms the complex treatment of the covalent bond in quantum mechanics into a simpler, if less precise, exercise in classical electrostatics. 

By exhibiting clearly the basic fact that electrons are wave-like fermions (de Broglie particles that obey the Pauli Exclusion Principle), the LMO-electride ion model of electronic structure enables one to utilize systematically many features of classical physics in developing an understanding , or explanation , of the properties of quantum mechanical systems. 

Below are five illustrative examples of the explanatory power of classical physics in structural chemistry. In these examples, classical electrostatic interactions are used with the electron-domain representation of molecules to explain or to derive The New Walsh Rules , the Langmuir-Pauling and Hendricks-Latimer Occupancy Rule, the s-character Rule, the Methyl Group — Tilt Rule, and the Octet Rule. 

The New Walsh Rules. Rules such as the rule that covalent molecules with three heavy atoms ( heavy atom = any atom other than hydrogen) and 18 valence-shell electrons are bent, while with 16 valence- 

The arrangement in space of 3 atomic cores and 9 (or 8) electron-pairs that has the lowest (most negative) coulombic energy is shown schematically in Fig. 10. Large circles represent valence-shell electron-pairs smaller circles labelled A, B, C represent the kernels of the three heavy atoms. For convenience, Fig. 10 has been drawn to show the approximate b solution for the problem in two dimensions. 

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