silicon dioxide

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Related to Amorphous silica: diatomaceous earth, Crystalline silica

silicon dioxide:

see silicasilica
or silicon dioxide,
chemical compound, SiO2. It is insoluble in water, slightly soluble in alkalies, and soluble in dilute hydrofluoric acid. Pure silica is colorless to white.
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silicon dioxide

[′sil·ə·kən dī′äk‚sīd]
(inorganic chemistry)
SiO2 Colorless, transparent crystals, soluble in molten alkalies and hydrofluoric acid; melts at 1710°C; used to make glass, ceramic products, abrasives, foundry molds, and concrete.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

silica, silicon dioxide

A white or colorless substance, nearly insoluble in water and in all acids except hydrofluoric; extremely hard; fuses to a colorless amorphous glass.
McGraw-Hill Dictionary of Architecture and Construction. Copyright © 2003 by McGraw-Hill Companies, Inc.

silicon dioxide

(SiO2) A hard, glassy mineral found in materials such as rock, quartz, sand and opal. In metal oxide semiconductor (MOS) chip fabrication, silicon dioxide is used to create the insulation layer between the metal gates of the top layer and the silicon elements below. See silica gel.
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References in periodicals archive ?
As expected, the sepiolite sample with the higher amount of extracted Mg becomes more similar to an amorphous silica, whose mass losses data from TGA are also reported in table 2.
Arnorsson, "Amorphous silica solubility and the thermodynamic properties of [H.sub.4]Si[O.sub.4] in the range of 0[degrees] to 350[degrees]C at [P.sub.sat]," Geochimica et Cosmochimica Acta, vol.
XRD of BS8 sample show amorphous silica along with some crystalline silica.
This toner contained 45% to 50% magnetite, with 45% to 50% styrene acrylic resin and less than 5% external additives, including hydrophobic amorphous silica and proprietary surface functional modifiers.
The aim of these experiments was to identify a set of conditions at which 0.2 m NaOH dissolves amorphous silica in soils from a temperate-humid climate, while minimising the attack of other Si compounds.
The final product of their study was white powder which turned out to amorphous silica. Muchidzuki et al.
RHA was obtained by burning rice husk at controlled temperature (650[degrees]C to 700[degrees]C) to achieve amorphous silica. XRD pattern of RHA used is given in Figure 1.
(3) In AAS paste, CSH changes into amorphous silica gel.
Because of their simple preparation and possible applications in several fields, dispersed, uniform, and amorphous silica nanoparticles have produced specific interest [4].
So far, the most widely studied matrix material is amorphous silica due to its high temperature stability and compatibility to versatile preparation methods [8-12].
RH is composed of 18% xylan, 22% lignin, 38% cellulose, 20% amorphous silica, and 2% other organic components [5].
Kanezashi et al., "Fabrication and characterization of porous amorphous silica tubes via the outsidevapor deposition method," Manuscript to be submitted.