Gillespie-Nyholm theory

Gibson model, 38 174-176 Gillespie-Nyholm valence shell electron-pair repulsion theory, 18 325 Glass-formers , 4 294 Glauber s salt, 4 17... 

Valence shell electron pair repulsion theory (VSEPR) provides a method for predicting the shape of molecules, based on the electron pair electrostatic repulsion. It was described by Sidgwick and Powell" in 1940 and further developed by Gillespie and Nyholm in 1957. In spite of this method s very simple approach, based on Lewis electron-dot structures, the VSEPR method predicts shapes that compare favorably with those determined experimentally. However, this approach at best provides approximate shapes for molecules, not a complete picture of bonding. The most common method of determining the actual stmctures is X-ray diffraction, although electron diffraction, neutron diffraction, and many types of spectroscopy are also used. In Chapter 5, we will provide some of the molecular orbital arguments for the shapes of simple molecules. 

The geometric structure of the covalent binary halides, whether neutral or complexed ions, can be explained on the basis of the Nyholm-Gillespie rules known as the Valence Shell Electron Pair Repulsion Model (VSEPR) theory the geometrical arrangements of the bonds around an atom in a species depends on the total number of electron pairs in the valence shell of the central atom, including both bonding... 

Gillespie, Ronald J., and Ronald S. Nyholm. Inorganic Stereochemistry. Quarterly Reviews of the Chemical Society (London) 11 (1957) 339-80. This essay introduced Valence Shell Electron Pair Repulsion (VSEPR) theory to the chemical community. 

The repulsion between charges is a general phenomenon for the forces determining the structure of compounds. Gillespie and Nyholm presented a very general rule for the influence of Coulomb interaction with the valence shell electron pair repulsion (VSEPR) theory. 

Molecular geometry is the general shape of a molecule as determined by the relative positions of the various atomic nuclei. A number of physical properties such as melting point, boiling point, density and a number of chemical properties are based on the molecular geometry. A very useful model to predict the general shape of a molecule was developed by Gillespie and Nyholm in 1957. The theory called the Valence Shell Electron Pair Repulsion (VSEPR pronounced as vesper) theory is an... 

In these compounds, xenon is in one of the following oxidation states Xe(II) in XeA2E3 types (three lone pairs) in the terminology of Gillespie and Nyholm s VSEPR theory of molecular structure, Xe(IV) in XeA4E2 types, Xe(VI) in XeA E or 0 = XeA4, and Xe(VIII) in XeO. Several reviews of noble gas chemistry, spectroscopy, and structure determination discuss the early work soon after the first discovery of a xenon compound in 1962. " Two comprehensive reviews published in 1970 and 1973, and the 1982 review by Seppelt and Lentz cover the later developments. ... 

One of the goals of the ELF approach is to provide an interpretative tool of quantum chemical calculations in terms of purely chemical concepts without the recourse to the nature of the approximate wave functions. The ELF recovers many features of the simple chemical models based on a spatial distribution of the valence electron, namely, the valence theory of G. N. Lewis, the mesomery concept of C. K. Ingold, and the VSEPR model of R. J. Gillespie and R. S. Nyholm. The partition of the electron density based on a statistical criterion provides a quantum mechanical support to the hypotheses which are explicitly or implicitly assumed in these models. Indeed, this statistical approach provides at least formally a mathematical bridge between quantum mechanics and chemistry which enables to critically think about the content and the definition of many chemical concepts related to the... 

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