|
Search over 100 encyclopedias and dictionaries: |
Research categories | Follow us on Twitter |
Research categories
View all topics in the newsView all reference sources at Encyclopedia.com |
|||
silica
silica or silicon dioxide, chemical compound, SiO 2 . It is insoluble in water, slightly soluble in alkalies, and soluble in dilute hydrofluoric acid. Pure silica is colorless to white. It occurs in several forms and is widely and abundantly distributed throughout the earth, both in the pure state and in silicates , e.g., in quartz (agate, amethyst, chalcedony, flint, jasper, onyx, and rock crystal), opal, sand, sandstone, clay, granite, and many other rocks; in skeletal parts of various protists and animals, such as certain sarcodines (see Sarcodina ), diatoms , and sponges , and in the stems and other tissue of higher plants. Silica has many important uses. It is used as a filler for paint and rubber; in making ordinary glass ; in ceramics; in construction; and in the preparation of other substances, e.g., silicon carbide . Fused quartz is pure amorphous silica; it is used in special chemical and optical apparatus. Because it has a low thermal coefficient of expansion, it withstands sudden changes in temperature and can be used in parts that are subjected to wide ranges of heat and cold. Unlike ordinary glass, it does not absorb infrared and ultraviolet light. |
|
|
Cite this article
"silica." The Columbia Encyclopedia, 6th ed.. 2011. Encyclopedia.com. 27 May. 2012 <http://www.encyclopedia.com>. "silica." The Columbia Encyclopedia, 6th ed.. 2011. Encyclopedia.com. (May 27, 2012). http://www.encyclopedia.com/doc/1E1-silica.html "silica." The Columbia Encyclopedia, 6th ed.. 2011. Retrieved May 27, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1E1-silica.html |
|
silica
silica Silicon dioxide (SiO2) which occurs naturally in three main forms: (a) crystalline silica includes the minerals quartz, tridymite, and cristobalite; (b) cryptocrystalline or very finely crystalline silica includes some chalcedony, chert, jasper, and flint; and (c) amorphous hydrated silica includes opal, diatomite, and some chalcedony. Coesite and stishovite are two high-density polymorphs of quartz which rarely occur in nature but have been synthesized experimentally.
|
|
|
Cite this article
AILSA ALLABY and MICHAEL ALLABY. "silica." A Dictionary of Earth Sciences. 1999. Encyclopedia.com. 27 May. 2012 <http://www.encyclopedia.com>. AILSA ALLABY and MICHAEL ALLABY. "silica." A Dictionary of Earth Sciences. 1999. Encyclopedia.com. (May 27, 2012). http://www.encyclopedia.com/doc/1O13-silica.html AILSA ALLABY and MICHAEL ALLABY. "silica." A Dictionary of Earth Sciences. 1999. Retrieved May 27, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O13-silica.html |
|
silica
silica Silicon dioxide (SiO2), which occurs naturally in three main forms: (a)crystalline silica includes the minerals quartz, tridymite, and cristobalite;(b)cryptocrystalline or very finely crystalline silica includes some chalcedony, chert, jasper, and flint; and(c)amorphous hydrated silica includes opal, diatomite, and some chalcedony.
|
|
|
Cite this article
MICHAEL ALLABY. "silica." A Dictionary of Ecology. 2004. Encyclopedia.com. 27 May. 2012 <http://www.encyclopedia.com>. MICHAEL ALLABY. "silica." A Dictionary of Ecology. 2004. Encyclopedia.com. (May 27, 2012). http://www.encyclopedia.com/doc/1O14-silica.html MICHAEL ALLABY. "silica." A Dictionary of Ecology. 2004. Retrieved May 27, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O14-silica.html |
|
silica
sil·i·ca / ˈsilikə/ • n. a hard, unreactive, colorless compound, SiO2, that occurs as the mineral quartz and as a principal constituent of sandstone and other rocks. DERIVATIVES: si·li·ceous / səˈlishəs/ (also si·li·cious) adj. |
|
|
Cite this article
"silica." The Oxford Pocket Dictionary of Current English. 2009. Encyclopedia.com. 27 May. 2012 <http://www.encyclopedia.com>. "silica." The Oxford Pocket Dictionary of Current English. 2009. Encyclopedia.com. (May 27, 2012). http://www.encyclopedia.com/doc/1O999-silica.html "silica." The Oxford Pocket Dictionary of Current English. 2009. Retrieved May 27, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O999-silica.html |
|
silica
|
|
|
Cite this article
"silica." World Encyclopedia. 2005. Encyclopedia.com. 27 May. 2012 <http://www.encyclopedia.com>. "silica." World Encyclopedia. 2005. Encyclopedia.com. (May 27, 2012). http://www.encyclopedia.com/doc/1O142-silica.html "silica." World Encyclopedia. 2005. Retrieved May 27, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O142-silica.html |
|
silica
silica silicon dioxide. XIX. f. L. silex, silic- flint.
So siliceous pert. to flint or silica. XVII. f. L. siliceus. silicium XIX, repl. by silicon XIX. Hence silicate (-ATE2) XIX. |
|
|
Cite this article
T. F. HOAD. "silica." The Concise Oxford Dictionary of English Etymology. 1996. Encyclopedia.com. 27 May. 2012 <http://www.encyclopedia.com>. T. F. HOAD. "silica." The Concise Oxford Dictionary of English Etymology. 1996. Encyclopedia.com. (May 27, 2012). http://www.encyclopedia.com/doc/1O27-silica.html T. F. HOAD. "silica." The Concise Oxford Dictionary of English Etymology. 1996. Retrieved May 27, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O27-silica.html |
|
silica
silica
•bicker, clicker, dicker, flicker, kicker, liquor, nicker, picker, pricker, shicker, slicker, snicker, sticker, ticker, tricker, vicar, whicker, Wicca, wicker
•bilker, milker, Rilke
•blinker, clinker, drinker, finca, freethinker, Glinka, Inca, inker, jinker, shrinker, sinker, Soyinka, stinker, stotinka, thinker, tinker, Treblinka, winker
•frisker, whisker
•kibitka, Sitka
•Cyrenaica • Bandaranaike
•perestroika • Baedeker • melodica
•Boudicca • trafficker • angelica
•replica
•basilica, silica
•frolicker, maiolica, majolica
•bootlicker • res publica • mimicker
•Anneka • arnica • Seneca • Lineker
•picnicker
•electronica, harmonica, Honecker, japonica, Monica, moniker, Salonica, santonica, veronica
•Guernica • Africa • paprika
•America, erica
•headshrinker • Armorica • brassica
•Jessica • lip-syncer • fossicker
•Corsica
•Attica, hepatica, sciatica, viatica
•Antarctica • billsticker
•erotica, exotica
•swastika
|
|
|
Cite this article
"silica." Oxford Dictionary of Rhymes. 2007. Encyclopedia.com. 27 May. 2012 <http://www.encyclopedia.com>. "silica." Oxford Dictionary of Rhymes. 2007. Encyclopedia.com. (May 27, 2012). http://www.encyclopedia.com/doc/1O233-silica.html "silica." Oxford Dictionary of Rhymes. 2007. Retrieved May 27, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O233-silica.html |
|
|
Search over 100 encyclopedias and dictionaries:
HighBeam™ Research, Inc. © Copyright 2012. All rights reserved.
The Encyclopedia.com advertising network includes:
