Silicic acid

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Silicic acid
Names
IUPAC name
Silicic acid
Other names
Monosilicic acid
Orthosilicic acid
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
ECHA InfoCard 100.109.340 Edit this at Wikidata
EC Number
  • 233-477-0
2009
  • InChI=1S/H4O4Si/c1-5(2,3)4/h1-4H checkY
    Key: RMAQACBXLXPBSY-UHFFFAOYSA-N checkY
  • InChI=1S/H4O4Si/c1-5(2,3)4/h1-4H
    Key: RMAQACBXLXPBSY-UHFFFAOYSA-N
  • InChI=1/H4O4Si/c1-5(2,3)4/h1-4H
    Key: RMAQACBXLXPBSY-UHFFFAOYAS
  • O[Si](O)(O)O
Properties
H4O4Si
Molar mass 96.113 g·mol−1
Acidity (pKa) 9.84, 13.2
Related compounds
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☒N verify (what is checkY☒N ?)
Annual mean sea surface silicic acid for the World Ocean. Data from the World Ocean Atlas 2005.

Silicic acid is a general name for a family of chemical compounds containing the element silicon attached to oxide and hydroxyl groups. This family of compounds have the general formula [SiOx(OH)4-2x]n.[1][2] Some simple silicic acids have been identified, but only in very dilute aqueous solution, such as metasilicic acid (H2SiO3), orthosilicic acid (H4SiO4, pKa1=9.84, pKa2=13.2 at 25 °C), disilicic acid (H2Si2O5), and pyrosilicic acid (H6Si2O7); however in the solid state these probably condense to form polymeric silicic acids of complex structure.

Preparation and occurrence

Silicic acids may be formed by acidification of silicate salts (such as sodium silicate) in aqueous solution. The main problem for the chemist is that these silicic acids readily lose water to form silica gel, a form of silicon dioxide. Such conversion involve condensations.

In the oceans, silicon exists primarily as orthosilicic acid (H4SiO4), and its biogeochemical cycle is regulated by the group of algae known as the diatoms.[3][4] These algae polymerise the silicic acid to so-called biogenic silica, used to construct their cell walls (called frustules).

Silicic acid in health

Continuing research of the correlation of aluminium and Alzheimer's disease has in the last few years included the use of silicic acid in beverages,[5][6][7] due to its abilities to both reduce aluminium uptake in the digestive system as well as cause renal excretion of aluminium.

Study has shown that physiological concentration of orthosilicic acid stimulates collagen type 1 synthesis and osteoblastic differentiation in human osteoblast-like cells in vitro.[8]

Choline-stabilized orthosilicic acid is a bioavailable nutritional supplement. It has been shown to prevent the loss of hair tensile strength,[9] have positive effect on skin surface and skin mechanical properties, and on brittleness of hair and nails,[10] abate brittle nail syndrome,[11] partially prevent femoral bone loss in the aged ovariectomized rat model,[12] increase collagen concentration in calves ,[13] and have potential beneficial effect on bone collagen formation in osteopenic females.[14]

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.
  3. ^ Siever, R. (1991). Silica in the oceans: biological-geological interplay. In: Schneider, S. H., Boston, P. H. (eds.), Scientists On Gaia, The MIT Press, Cambridge MA, USA, pp. 287-295.
  4. ^ Treguer, P., Nelson, D. M., Van Bennekom, A. J., DeMaster, D. J., Leynaert, A. and Queguiner, B. (1995). The silica balance in the world ocean: A reestimate. Science 268, 375-379.
  5. ^ Exley C, Korchazhkina O, Job D, Strekopytov S, Polwart A, Crome P (2006). "Non-invasive therapy to reduce the body burden of aluminium in Alzheimer's disease". J. Alzheimers Dis. 10 (1): 17–24, discussion 29–31. PMID 16988476.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  6. ^ González-Muñoz MJ, Peña A, Meseguer I (2008). "Role of beer as a possible protective factor in preventing Alzheimer's disease". Food Chem. Toxicol. 46 (1): 49–56. doi:10.1016/j.fct.2007.06.036. PMID 17697731.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  7. ^ Gonzalez-Muñoz MJ; Meseguer I; Sanchez-Reus MI; et al. (2008). "Beer consumption reduces cerebral oxidation caused by aluminum toxicity by normalizing gene expression of tumor necrotic factor alpha and several antioxidant enzymes". Food Chem. Toxicol. 46 (3): 1111–8. doi:10.1016/j.fct.2007.11.006. PMID 18096288. {{cite journal}}: Unknown parameter |author-separator= ignored (help)
  8. ^ Reffitt DM; Ogston N; Jugdaohsingh R; et al. (2003). "Orthosilicic acid stimulates collagen type 1 synthesis and osteoblastic differentiation in human osteoblast-like cells in vitro". Bone. 32 (2): 127–35. doi:10.1016/S8756-3282(02)00950-X. PMID 12633784. {{cite journal}}: Unknown parameter |author-separator= ignored (help)
  9. ^ Wickett RR; Kossmann E; Barel A; et al. (2007). "Effect of oral intake of choline-stabilized orthosilicic acid on hair tensile strength and morphology in women with fine hair". Arch. Dermatol. Res. 299 (10): 499–505. doi:10.1007/s00403-007-0796-z. PMID 17960402. {{cite journal}}: Unknown parameter |author-separator= ignored (help)
  10. ^ Barel A; Calomme M; Timchenko A; et al. (2005). "Effect of oral intake of choline-stabilized orthosilicic acid on skin, nails and hair in women with photodamaged skin". Arch. Dermatol. Res. 297 (4): 147–53. doi:10.1007/s00403-005-0584-6. PMID 16205932. {{cite journal}}: Unknown parameter |author-separator= ignored (help)
  11. ^ Scheinfeld N, Dahdah MJ, Scher R (2007). "Vitamins and minerals: their role in nail health and disease". J Drugs Dermatol. 6 (8): 782–7. PMID 17763607.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  12. ^ Calomme M; Geusens P; Demeester N; et al. (2006). "Partial prevention of long-term femoral bone loss in aged ovariectomized rats supplemented with choline-stabilized orthosilicic acid". Calcif. Tissue Int. 78 (4): 227–32. doi:10.1007/s00223-005-0288-0. PMID 16604283. {{cite journal}}: Unknown parameter |author-separator= ignored (help)
  13. ^ Calomme MR, Vanden Berghe DA (1997). "Supplementation of calves with stabilized orthosilicic acid. Effect on the Si, Ca, Mg, and P concentrations in serum and the collagen concentration in skin and cartilage". Biol Trace Elem Res. 56 (2): 153–65. doi:10.1007/BF02785389. PMID 9164661.
  14. ^ Spector TD; Calomme MR; Anderson SH; et al. (2008). "Choline-stabilized orthosilicic acid supplementation as an adjunct to Calcium/Vitamin D3 stimulates markers of bone formation in osteopenic females: a randomized, placebo-controlled trial". BMC Musculoskelet Disord. 9: 85. doi:10.1186/1471-2474-9-85. PMC 2442067. PMID 18547426. {{cite journal}}: Unknown parameter |author-separator= ignored (help)CS1 maint: unflagged free DOI (link)
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