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Encyclopedia > Silicic acid

Silicic acid is a general name for a family of chemical compounds of silicon, hydrogen, and oxygen, with the general formula [SiOx(OH)4-2x]n. Some simple silicic acids have been identified in very dilute aqueous solution, such as metasilicic acid (H2SiO3), orthosilicic acid (H4SiO4), disilicic acid (H2Si2O5), and pyrosilicic acid (H6Si2O7); however in the solid state these probably condense to form polymeric silicic acids of complex structure. General Name, Symbol, Number silicon, Si, 14 Chemical series metalloids Group, Period, Block 14, 3, p Appearance dark gray, bluish tinge Atomic mass 28. ... General Name, Symbol, Number hydrogen, H, 1 Chemical series nonmetals Group, Period, Block 1, 1, s Appearance colorless Atomic mass 1. ... General Name, Symbol, Number oxygen, O, 8 Chemical series nonmetals Group, Period, Block 16, 2, p Appearance colorless Atomic mass 15. ...


Silicic acids may be formed by acidification of silicate salts (such as sodium silicate) in aqueous solution. When heated they lose water to form silica gel, an active form of silicon dioxide. In chemistry, a silicate is a compound consisting of silicon and oxygen (SixOy), one or more metals, and possibly hydrogen. ... In chemistry, salt is a term used for ionic compounds composed of positively charged cations and negatively charged anions, so that the product is neutral and without a net charge. ... Sodium silicate, also known as water glass, is a compound used in cements and textile processing. ... Some examples of silica gel sachets Silica gel is a granular, porous form of silica made synthetically from sodium silicate. ... The chemical compound silicon dioxide, also known as silica, is the oxide of silicon, chemical formula SiO2. ...


In the oceans, silicon exists primarily as orthosilicic acid (H4SiO4), and its cycle is regulated by the group of algae known as the diatoms. These algae polymerise the silicic acid to so-called biogenic silica, used to construct their cell walls (called frustules). Ocean (from Okeanos, a Greek god of sea and water; Greek ωκεανός) covers almost three quarters (71%) of the surface of the Earth, and nearly half of the worlds marine waters are over 3000 m deep. ... A seaweed (Laurencia) up close: the branches are multicellular and only about 1 mm thick. ... Diatoms are a major group of eukaryotic algae, and are one of the most common types of phytoplankton. ... A polymer is not a generic term used to describe a substantially long molecule. ... A cell wall is a more or less solid layer surrounding a cell. ...


References

  1. N. N. Greenwood, A. Earnshaw, Chemistry of the Elements, 2nd ed., Butterworth-Heinemann, Oxford, UK, 1997.
  2. R. K. Iler, The Chemistry of Silica, Wiley, New York, 1979.

  Results from FactBites:
 
COGIMAX (817 words)
Silicic acid and mineral silicates are the active forms of silica and silicon in both plants and animals.
Silicic acid and silicates increase the production of collagen by several mechanisms, one of which is the stimulation of an enzyme involved in the conversion of procollagen to collagen.
Bioactive silicates increase the hydration of extracellular substances, and therefore adequate intake of water is required to replenish the extracellular interstitial fluid.
Process for extracting pure, coarse grain silicic acid crystals from spent lye - Patent 5730838 (2953 words)
It is an object of the present invention that the silicic acid obtained in the overflow of the washing phase is introduced directly into the spent lye to be desilicified in the alkalizing container or in a dissolving container upstream of same.
The contents in silicic acid is kept in all precipitation steps higher than 10 g/l through recycling into coarse crystalline silicic acid and the silicic acid precipitated per hour in the step which represents approximately 10% of the total silicic acid present in the step is conveyed to the crystallization step by means of inoculating.
The coarse-grain silicic acid fraction is fed in major part to the first crystallization vessel 2 for inoculating and raising of the silicic acid contents of the spent lye to be desilified.
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