Hydrated silica

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Hydrated Silica is a form of silicon dioxide, which has a variable amount of water in the formula. It is also known as silicic acid, a term usually used for its form dissolved in water. It is found in nature, as opal, which has been mined as a gemstone for centuries and in the cell walls of diatoms. It is also manufactured for use in toothpaste. Once dehydrated the gel is used as a dessicant known as Silica Gel. It is also used in various paints and varnishes and in the production of beer.

Contents 1 Nature 2 Chemical Formula 3 Use in toothpaste 4 Safety 5 References

[edit] Nature

In its pure form, as manufactured for toothpaste, it is an odourless, tasteless, white, gelatinous substance, which is chemically inert.

[edit] Chemical Formula

Chemical Formula: SiO2 · nH2O

SiO2 = 1,   H2O = 1:     H2SiO3 
SiO2 = 2,   H2O = 1:     H2Si2O5 
SiO2 = 2,   H2O = 3:     H6Si2O7 
SiO2 = 3,   H2O = 2:     H4Si3O8 
SiO2 = 3,   H2O = 4:     H8Si3O10 
SiO2 = 4,   H2O = 1:     H2Si4O9 
SiO2 = 4,   H2O = 2:     H4SiO4 [also known as Si(OH)4 ]

[edit] Use in toothpaste

Hydrated Silica is a mild gel abrasive, which, when combined with calcium carbonate (from chalk) helps to remove plaque. Milled to a slightly larger size, the grains are more abrasive and will help to whiten teeth.

[edit] Safety

Hydrated Silica is listed by the US Food and Drug Administration as 'Generally Recognised as Safe'

[edit] References

Toothpaste: [1] Chemistry: [2] Opal: [3] Paint/Varnish: [4] Beer: [5]