Silicon Dioxide Silica

CHEMICAL NAME = silicon dioxide CAS NUMBER = 14808-60-7 MOLECULAR FORMULA = Si02 MOLAR MASS = 60.1 g/mol COMPOSITION = Si(46.7%) 0(53.3%) 

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Because carbon stands at the head of its group, we expect it to differ from the other members of the group. In fact, the differences between the element at the head of the group and the other elements are more pronounced in Group 14/IV than anywhere else in the periodic table. Some of the differences between carbon and silicon stem from the smaller atomic radius of carbon, which explains the wide occurrence of C=C and G=Q double bonds relative to the rarity of Si=Si and Si=0 double bonds. Silicon atoms are too large for the side-by-side overlap of p-orbitals necessary for -it-bonds to form between them. Carbon dioxide, which consists of discrete 0=C=0 molecules, is a gas that we exhale. Silicon dioxide (silica), which consists of networks of —O—Si- O - groups, is a mineral that we stand on. 

The main source of silicon for semiconductor chips is silicon dioxide (silica). Silica can be reduced directly to elemental form by intense heating with coke in an electric arc furnace. At the temperature of the furnace, silicon is... 

Dusting Powders are sprinkled onto the intact skin and consist of talc, magnesium stearate, silicon dioxide (silica), or starch. They adhere to the skin, forming a low-friction film that attenuates mechanical irritation. Powders exert a drying (evaporative) effect. 

Silicon dioxide (silica), which consists of networks of —O—Si—O— groups, is a mineral we stand on. 

Other metal carbonates behave similarly (i.e., the oxides are formed during the ashing procedure). The stable mineral quartz (silicon dioxide, silica, Si02) is the only major mineral found in coal that is inert during high-temperature ashing. 

See Selenium Oxygen, Organic matter 4833. Silicon dioxide (Silica)... 

Silicon dioxide (silica, Si02) has a similar 3D structure and properties. The hardness of diamond enables it to be used as the leading edge on cutting tools. 

Sea sand is primarily comprised of silicon dioxide (silica), which may be converted to elemental silicon (96-99% purity) through reaction with carbon sources such as charcoal and coal (Eq. 2). Use of a slight excess of Si02 prevents silicon carbide (SiC) from forming, which is a stable product at such a high reaction temperature. Scrap iron is often present during this transformation in order to yield silicon-doped steel as a useful by-product. 

SAFETY PROFILE A nuisance dust. Moderately toxic by ingestion. An eye irritant. Does not occur freely in nature, but is found as silicon dioxide (silica) and as various silicates. Elemental Si is flammable when exposed to flame or by chemical reacdon with oxidizers. Violent reactions with alkali carbonates, oxidants, (A1 + PbO), Ca, CS2C2, CI2, C0F2, F2, IF5, Mnp3, Rb2C2, FNO, AgF, NaK alloy. When heated it will react with water or steam to produce H2 can react with oxidizing materials. See also various silica entries, SILICATES, and POWDERED METALS. 

Natural silicon-based fillers are divided into hydrated silicas and silicon dioxide (silicas) on the one hand, and silicates, on the other. There is no sharp dividing line between these two groups, since the former do not always occur in a pure form and may contain silicates together... 

Silicon dioxide (silica) exists in two familiar forms in nature quartz, small chips of which occur in sand and flint (Latin fe), an uncrystallized amorphous type of silica. Silica is properly represented as (Si02) because it is a polymeric solid of SiO tetrahedra sharing all oxygens among surrounding tetrahedra (Eigure 13-32c). Eor comparison, solid carbon dioxide (dry ice) consists of discrete 0=C=0 molecules, as does gaseous CO2. 

Silicon dioxide, silica, can be natural or synthetic, crystalline or amorphous. This book is concerned mostly with synthetic amorphous silica in the colloidal state. 

Silicon Dioxide. Silica silicic anhydride. 02Si mol wt 60.09. O 53.25%, Si 46.75%. Si02. Occurs in nature as agate, amethyst, chalcedony, cristobalite, flint, quartz, sand, tridymite. Reviews Several authors in Kirk-Othmer Encyclopedia of Chemical Technology vol. 18 (Interscience. New York, 2nd ed., 1969) pp 46.111 Rochow in Comprehensive Inorganic Chemistry vol. 1, I. C. Bailar, Jr. et al Eds. (Pergamon Press, Oxford, 1973) pp 1388-1402. 

Aggregate, alumiiia (alumiiium oxide), cement raw mix, clay, dolomite, fluorspar, kaolin, light weight aggregate, lime, limestone, magnesia (magnesium oxide), pigments, silica (silicon dioxide), silica fume Products... 

Note Does not occur free In nature, but Is found In silicon dioxide (silica) 8 in various silicates.]... 

Synonyms Colloidal silica Colloidal silicon dioxide Silica sol Silicon dioxide colloidal... 

Quartz is a widely distributed mineral species consisting of silicon dioxide (silica, SiOj) (Table 7.6). It is one of the most common minerals and is found in many varieties with very diverse modes of occurrence. Quartz is a primary constituent of rocks such as granite, quartz, porphyry, and rhyolite. It is also a common constituent in many gneisses (laminate rocks) and crystalline schists (foliated rocks). It is also, in a sense, mobile since by the weathering of silicates, silica passes into solution and is redeposited in cavities, crevices, and along joints of rocks of all types. Thus, it is not... 

Siiica Bead SB-145] Siiica Bead SB-150] Siiica Bead SB-300] Siiica Bead SB-700. See Silica Silic acid (polyortho). See Silica, hydrated Silica, colloidal EINECS/ELINCS 231-545-4 Synonyms Colloidal silica Colloidal silicon dioxide Silica sol Silicon dioxide colloidal Definition A stable dispersion of discrete, colloid-size particles of amorphous silica in aq. sol n. 

Next to oxygen, silicon is the most common substance in our environment. Silicon has never been found in its elementary state. In nature it exclusively occurs in compounds derived from silicon dioxide (silica = Si02). Silica is a regular constituent part in about 92% of all sorts of rock. 

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