silica

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Same as silicon dioxide.

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A white or colorless substance, nearly insoluble in water and in all acids except hydrofluoric; extremely hard; fuses to a colorless amorphous glass.

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silicon(iv) oxide; silicon dioxide; SiO₂; a colourless or white solid used in many chromatographic procedures; silicic acid contains silanol (def. 4) groups to some of which water is bound. For chromatographic use, it is heated to 100°C to drive out this water. Heating above 170°C causes formation of oxide linkages (Si−O−Si), and at very high temperatures (800 — 1000°C) it forms glass. Silicic acid is available in a variety of particle sizes. For chromatography, these range from 10 to 500 µm, the larger sizes being used for column chromatography at normal pressures, the smaller sizes for thin layer chromatography and high-pressure liquid chromatography. Silica gel is silicic acid precipitated as granules, about 3 mm diameter; it is hygroscopic and used as a drying agent, which can be re-used after heating. A powder of very fine silica particles, 0.007 — 0.014 µm, known as fumed silica, has thixotropic properties and has been used to create a gel in organic solvents, e.g. in scintillation cocktails to maintain hydrophilic materials in suspension during counting (now superseded by cocktails that themselves form a gel with water). Silica is found in certain algae, notably in the hard shell, or test, of diatoms (see silaffin); it also serves to reinforce the stems of the primitive vascular plants known as horsetails.

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Silicon dioxide, a compound occurring naturally as quartz and in other forms. A common constituent of urinary calculi in agricultural animals, a rare occurrence in dogs.

• s. calculi — see silica urolith.
• s. gel — commonly used in the laboratory as a desiccant; has been used topically on dogs and cats for flea control.

(sil′ikə)
n
quartz

The purest of three major ingredients that make up dental porcelain. It imparts stiffness and hardness to the product and is the framework around which the kaolin and feldspar contract.

For a list of words related to silica, see:

• Materials, Formations, and Substances - silica: silicon dioxide that occurs as crystalline quartz, opal, or sand

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See words rhyming with "silica."

  See crossword solutions for the clue Silica.

Dansk (Danish)
n. - kiselsyreanhydrid, kiselsyre

Nederlands (Dutch)
kiezelaarde

Français (French)
n. - silice

Deutsch (German)
n. - Kieselerde

Ελληνική (Greek)
n. - (ορυκτολ.) πυριτία

Italiano (Italian)
silice

Português (Portuguese)
n. - sílica (f) (Quím.)

Русский (Russian)
кварц, двуокись кремния

Español (Spanish)
n. - sílice

Svenska (Swedish)
n. - kiseldioxid, kiselsyra

中文（简体）(Chinese (Simplified))
硅石, 硅土, 无水硅酸

中文（繁體）(Chinese (Traditional))
n. - 矽石, 矽土, 無水矽酸

한국어 (Korean)
n. - 실리카, 무수규산, 규토

日本語 (Japanese)
n. - 珪酸, 二酸化珪素

العربيه (Arabic)
‏(الاسم) ثاني أوكسيد ألسليكون‏

עברית (Hebrew)
n. - ‮דו-תחמוצת הצורן‬

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