Compounds of silicon

Substances which have a deleterious effect on the taste and/or smell of the products for human consumption derived from the aquatic environment Toxic or persistent organic compounds of silicon Inorganic compounds of phosphorus and elemental phosphorus Non-persistent mineral oils and hydrocarbons of petroleum origin Cyanides, fluorides... 

Both acids form compounds of silicon as a result of attack on the network, silicon fluoride from hydrofluoric acid and silicyl phosphate from phosphoric acid. 

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. 

Molecular compounds of silicon in a formally zerovalent oxidation state can be stabilized by appropriate transition-metal fragments. An entry to such polyme-tallated complexes of silicon is given by the chlorosilylene compounds 7, 11 as a starting-point. 

Silicon Epitaxy. Silicon epitaxial films have superior properties. The applications are, however, limited by the high temperature of deposition, which is generally above 1000°C. These reactions use chlorinated compounds of silicon (tetrachloride, trichlorosilane, or dichlorosilane) as precursors as follows ... 

Compounds of silicon with oxygen are prevalent in the Earth s crust. About 95% of crastal rock and its various decomposition products (sand, clay, soil) are composed of silicon oxides. In fact, oxygen is the most abundant element in the Earth s crast (45% by mass) and silicon is second (27%). In the Earth s surface layer, four of every five atoms are silicon or oxygen. 

The most abundant compounds of silicon are Si02 and the related silicate anions, all of which contain Si—O bonds. See Sections 9.3 and 10.3 for descriptions of the structure and bonding of these compounds, which involve a bond networks and tetrahedral geometry. As already mentioned, many minerals are combinations of hard silicate... 

Sekiguchi, Akira, and Sakurai, Hideki, Cage and Cluster Compounds of Silicon, Germanium, and Tin. 37 1... 

Silicon-containing ceramics include the oxide materials, silica and the silicates the binary compounds of silicon with non-metals, principally silicon carbide and silicon nitride silicon oxynitride and the sialons main group and transition metal silicides, and, finally, elemental silicon itself. There is a vigorous research activity throughout the world on the preparation of all of these classes of solid silicon compounds by the newer preparative techniques. In this report, we will focus on silicon carbide and silicon nitride. 

The elements of Group IV are found almost everywhere. All living things contain compounds of carbon, and most of the earth s sand, soil, and many of its rocks contain compounds of silicon. The five elements of this important group are ... 

Operation of detectors with their associated alarm panels should be checked and calibrated after installation. Detector performance can be impaired in a hostile environment by blockages to the detector (i.e., ice, salt crystals, wind blown particles, water or even fire fighting foam, or by inhibition of the catalysts by airborne contaminants such as compounds of silicon, phosphorus, chlorine or lead. It is essential that detectors and alarm panels be checked and re-calibrated on a routine basis. 

These reactions have been extensively studied for optically inactive compounds of silicon and first row transition-metal carbonyls. ... 

Qualitatively and quantitatively, compounds of silicon and oxygen are the class of substances of greatest importance in the earth s crust and mantle, in regard to both mass and variety of structural forms. 

Optical fibres need to be free of impurities such as transition metal ions (see Chapter 8) and conventional methods of preparing silica glasses are inadequate. The sol-gel process is one way of forming fibres of sufficient purity (chemical vapour deposition. Section 3.7, is another). These processes use volatile compounds of silicon which are more easily purified, for example by fractional distillation, than silica. It is possible to produce silica fibres using a method similar to that studied in the nineteenth century, but with the geldrying time reduced from a year to a few days. Liquid silicon alkoxide (Si(OR)4), where R is methyl, ethyl, or propyl, is hydrolysed by mixing with water. 

Among the useful compounds of silicon are silicon carbide (carborundum) and silicon nitride, which are hard, tough materials used for making cutting tools, abrasives, and engineering... 

A bond between two lead atoms is found46 in hexamethyl dilead, Pbj(CH ) . The Pb—Pb bond length, 2.88 0.03 A, is about that expected from the tetrahedral radius of lead, as is the Pb—C bond length, 2.25 0.0G A. This substance is, of course, similar to hexa-methyletham and the corresponding compounds of silicon, germanium, and tin. 

This enhanced reactivity of compounds of silicon and phosphorus is typical of all of the heavier nonmetals in contrast to the elements of the second row. 

SlUCIFlED MEMBRANE A membrane that has been replaced or impregnated by a compound of silicon. 

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