Structural chemistry of silicon

After oxygen (approx 45.5 wt%), silicon is the next most abundant element in the earth s crust (approx 27 wt%). Elemental Si does not occur naturally, but it combines with oxygen to form a large number of silicate minerals. 

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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. 

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. 

Bokii, N. G., Shklover, V. E., Struchkov, Yu. I., Structural Chemistry of Organic Derivatives of Nontransition Elements. Structural Chemistry of Silicon, Germanium, Tin, and Lead Organic Compounds, Itogi Nauki Tekh. Kristallokhim. 10 [1974] 94/148. 

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 chemistry of silicon in very low oxidation states is one of the most fascinating research areas, which can be located between molecular compounds of silicon and elemental (perhaps amorphous) silicon [190-194]. Most interesting results have recently been obtained by structural investigations of siliddes in Zintl phases. However, compounds of silicon with negative oxidation states and very low coordination numbers of 1, 2, and 3 are so far only known in the composite of a crystal lattice. 

The chemistry of silicone halides was recently reviewed by Collins.13 The primary use for SiCU is in the manufacturing of fumed silica, but it is also used in the manufacture of polycrystalline silicon for the semiconductor industry. It is also commonly used in the synthesis of silicate esters. T richlorosilane (another important product of the reaction of silicon or silicon alloys with chlorine) is primarily used in the manufacture of semiconductor-grade silicon, and in the synthesis of organotrichlorosilane by the hydrosilylation reactions. The silicon halohydrides are particularly useful intermediate chemicals because of their ability to add to alkenes, allowing the production of a broad range of alkyl- and functional alkyltrihalosilanes. These alkylsilanes have important commercial value as monomers, and are also used in the production of silicon fluids and resins. On the other hand, trichlorosilane is a basic precursor to the synthesis of functional silsesquioxanes and other highly branched siloxane structures. 

The unique surface characteristics of polysiloxanes mean that they are extensively used as surfactants. Silicone surfactants have been thoroughly studied and described in numerous articles. For an extensive, in-depth discussion of this subject, a recent chapter by Hill,476 and his introductory chapter in the monograph he later edited,477 are excellent references. In the latter monograph, many aspects of silicone surfactants are described in 12 chapters. In the introduction, Hill discusses the chemistry of silicone surfactants, surface activity, aggregation behavior of silicone surfactants in various media, and their key applications in polyurethane foam manufacture, in textile and fiber industry, in personal care, and in paint and coating industries. All this information (with 200 cited references) provides a broad background for the discussion of more specific issues covered in other chapters. Thus, surfactants based on silicone polyether co-polymers are surveyed.478 Novel siloxane surfactant structures,479 surface activity and aggregation phenomena,480 silicone surfactants application in the formation of polyurethane foam,481 foam control and... 

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. 

Several excellent reviews are available concerning both surface structure of semiconductors and surface chemistry of semiconductors, including Refs. [5-23]. Here, a comprehensive review is not attempted and the reader is referred instead to those references. The focus of this chapter is primarily on the surface chemistry of silicon and germanium, as these are the two most heavily studied systems. We strive to provide insight into the chemical reactivity of these two surfaces, and hence... 

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. 

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... 

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