Silicon, structural chemistry

Boron (like silicon) invariably occurs in nature as 0X0 compounds and is never found as the element or even directly bonded to any other element than oxygen. The structural chemistry of B-O compounds is characterized by an extraordinary complexity and diversity which rivals those of the borides (p. 145) and boranes (p. 151). In addition, vast numbers of predominantly organic compounds containing B-O are known. 

F. Liebau, Silicon, element 14, in K. H. Wedepohl (ed.). Handbook of Geochemistry, Vol. 11-2, Chap. 14, Springer-Verlag, Berlin, 1978. F. Liebau, Structural Chemistry of Silicates, Springer-Verlag, Berlin, 1985, 347 pp. 

The present volume comprises 17 chapters, written by 27 authors from 11 countries, and deals with theoretical aspects and structural chemistry of peroxy compounds, with their thermochemistry, O NMR spectra and analysis, extensively with synthesis of cyclic peroxides and with the uses of peroxides in synthesis, and with peroxides in biological systems. Heterocyclic peroxides, containing silicon, germanium, sulfur and phosphorus, as well as transition metal peroxides are treated in several chapters. Special chapters deal with allylic peroxides, advances in the chemistry of dioxiranes and dioxetanes, and chemiluminescence of peroxide and with polar effects of their decomposition. A chapter on anti-malarial and anti-tumor peroxides, a hot topic in recent research of peroxides, closes the book. 

Heller, G. 1986. A survey of structural types of borates and polyborates. Pages 39-100 in P.L. Boschke (ed.). Structural Chemistry of Boron arul Silicon. Springer-Verlag, Berlin. 

Structural Chemistry of Boron and Silicon. Springer-Verlag, Berhn. 

II. SINGLE BONDS TO SILICON A. Structural Chemistry of the Si—C Bond... 

Most of the organosilicon compounds contain bonds between the silicon and carbon atom. In the following paragraph the structural chemistry of the Si—C single bond is discussed, mostly in compounds with tetracoordinate silicon and tetracoordinate carbon atoms. The structural chemistry of the Si—C bond in compounds where the carbon coordination state is different, is also discussed. The Si—C bond is markedly polarized and the increase of the bond ionicity by attaching different substituents to either the silicon or the carbon atoms may affect its length. The electronic and steric effects are discussed later. 

The structural chemistry of silicon bonded to special functional groups such as acetyl group, cyanide and isocyanide deserves special attention. Acylsilanes having the general formula l SiC.OR constitute an interesting class of chemical compounds. They are sensitive to light and rather unstable, particularly in a basic environment, where they react... 

There has been particular interest in the chemistry of small organosilicon ions and their neutral counterparts for a number of reasons (i) Small SiCvHv molecules are well suited to draw analogies between the structural chemistry of silicon and carbon—or to state differences, (ii) The chemistry of small silicon compounds is viewed as fundamental in astrophysics and astrochemistry, and a large number of cationic and neutral SiRv molecules have been detected in interstellar and circumstellar matter. 

Since 1990, several reviews have appeared covering silicon-chalcogen chemistry. These include the spectroscopic properties of silicon-sulphur compounds along with structural data1. The synthesis of metal-chalcogen clusters using (Me3Si)2X (X = S, Se,... 

W. S. Sheldrick, Structural Chemistry of Organic Silicon Compounds , in The Chemistry of Organic Silicon Compounds (Eds. S. Patai and Z. Rappoport), Wiley, New York, 1989. 

The following review is concerned with the synthetic and structural chemistry of molecular alumo-siloxanes, which combine in a molecular entity the elements aluminum and silicon connected by oxygen. They may be regarded as molecular counterparts of alumo-silicates, which have attracted considerable attention owing to their solid-state cage structures (see for example zeolites).1 3 Numerous applications have been found for these solid-state materials for instance the holes and pores can be used in different separation techniques.4,5 Recently the channel and pore structures of zeolites and other porous materials have been used as templates for nano-structured materials and for catalytical purposes.6 9... 

Scheme 8.10. Silicon-based chemistry has led to the creation of novel Fe and Co terminated structures.

The most important recent developments in the structural chemistry of silicon have involved non-tetracoordinate derivatives. In the last 20 years there was an ever increasing interest to penta- and hexa-coordinate silicon compounds. New classes of these compounds were discovered and studied in detail. This progress was stimulated by the development of new experimental techniques and theoretical approaches as well as the specific biological activity finding for some of silicon compounds with expanded coordination sphere. 

Library of Congress Cataloging-in-Publication Data. Main entry under title Structural chemistry of boron and silicon (Topics m current chemistry 131)... 

The pseudorotation phenomenon is vital to structural chemistry of phosphorus, silicon, transitional metals, and some other elements. Apart from pseudorotation, there are other rearrangement mechanisms, for example, trigonal twist (Fig. 48a) examined in dynamic stereochemistry of icosahedral carboranes, tourniquet mechanism (Fig. 486), etc. 

When the divalent cation becomes too large for the spinel structure to be adopted (e.g. Ca +, Ba +, andPb +), atridymite (Si02) stmcture is obtained that has the divalent cation in the interstices see Silicon Inorganic Chemistry). These are synthesized by reaction of the oxides at temperatures over 800 °C. The barium and calcium derivatives are used in ceramics and refractories. In particular, BaAl204 is used... 

Aluminosilicates form an extensive family of compounds that include layered compounds (such as clays, talc, and micas), 3-D compounds, (e.g. feldspars, such as granite), and microporous solids known as molecular sieves. The structural diversity of these materials is contributed to by aluminum s ability to occupy both tetrahedral and octahedral holes as it also does in y-Al203. Thus, aluminum substitution for silicon in silicate minerals may lead to replacement of silicon in tetrahedral sites or the aluminum can occupy an octahedral environment external to the silicate lattice. Replacement of Si with Al requires the presence of an additional cation such as H+, Na+, or 0.5 Ca + to balance the charge. These additional cations have a profound effect on the properties of the aluminosilicates. This accounts for the many types of layered and 3-D structures (see Silicon Inorganic Chemistry). 

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