Hydrated silica
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Hydrated silica is a form of silicon dioxide, which has a variable amount of water in the formula. When dissolved in water it is usually known as silicic acid. 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. Hydrated silica can be dehydrated to produce silica gel[citation needed], which is used as a desiccant. It is also used in various paints and varnishes and in the production of beer.
Nature[]
In its pure form, as manufactured for toothpaste, it is an odorless, tasteless, white, gelatinous substance, which is chemically inert.
Chemical formula[]
Chemical Formula: SiO2 · nH2O
- 1 SiO2 + 1 H2O → H2SiO3
- 1 SiO2 + 2 H2O → H4SiO4 [also known as Si(OH)4]
- 2 SiO2 + 1 H2O → H2Si2O5
- 2 SiO2 + 3 H2O → H6Si2O7
- 3 SiO2 + 2 H2O → H4Si3O8
- 3 SiO2 + 4 H2O → H8Si3O10
- 4 SiO2 + 1 H2O → H2Si4O9
Use in toothpaste[]
Diatomaceous earth, originally mined as "tooth powder" is a naturally occurring hydrated silica. As a fine gel abrasive, frequently combined with softer calcium carbonate (from chalk) it helps to remove plaque. Milled to a slightly larger size, the grains are more aggressive and are used in tooth bleaching formulations.
Flame retardant[]
It also has synergetic effects when compounded with traditional flame retardants such as magnesium hydroxide and aluminium hydroxide.[citation needed]
Safety[]
Hydrated silica is listed by the US Food and Drug Administration as "Generally Recognized as Safe".
References[]
This article includes a list of references, related reading or external links, but its sources remain unclear because it lacks inline citations. (November 2019) |
Toothpaste: [1] Chemistry: [2][unreliable source?] Opal: [3] Paint/Varnish: [4] Beer: [5]
- Household chemicals
- Silicon dioxide