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.

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.

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.
References in periodicals archive ?
2 m NaOH dissolves amorphous silica in soils from a temperate-humid climate, while minimising the attack of other Si compounds.
It is worth mentioning that amorphous silica was also extracted by other researchers [2, 5, 6, 9, 13] from the RHA by using other methods.
High-purity Amorphous Silica Originated in Rice Husks via Carboxylic Acid Leaching Process, Journal of Materials Science, 43: 7084-7090.
The most pervasively altered samples look as a criptocrystalline mass with clay minerals and amorphous silica, while samples moderately altered show relictic forms of preexisting minerals as plagioclase and pyroxenes, these minerals were replaced by kaolinite, albite and some other unidentified clay minerals in thin section, by XRD was possible to identify clay minerals using the methodology described by Thorez, J.
Using the phenol test (Johansen 1940), Ciciarelli (1986, 1987, 1989) reported the presence of amorphous silica in hypodermal cells and tissues surrounding secondary veins of C.
Chrzan and his colleagues found that when germanium tin nanocrystals were embedded within amorphous silica the nanocrystals formed a bilobed nanostructure that was half crystalline metallic and half crystalline semiconductor.
2]] nanocomposites reveal PbS nanocrystals of high contrast widely dispersed throughout the amorphous silica xerogel matrix.
A preliminary assessment of the ure of an amorphous silica residual as a supplementary cementing materials.
Based on a PhD research program carried out by the author, this book presents an approach to investigating the mechanisms of amorphous silica and calcium oxalate composite fouling on the heat exchanger surface of sugar mill evaporators.
In fact these stones are nothing more than amorphous silica containing up to a fifth of water, with traces of metal oxides that sparkle.
The phases of the 550[degrees]C composite coating include [gamma]-alumina and amorphous silica.
The transparent solid is similar in structure to the ordinary amorphous silica in window glass.