Silanol
 | This article needs additional citations for verification. (December 2009) |
| |||
| Names | |||
|---|---|---|---|
| IUPAC name
Silanol
| |||
| Systematic IUPAC name
Silanol[1] (substitutive) | |||
| Other names
Hydroxysilane
Silicol | |||
| Identifiers | |||
3D model (JSmol)
|
|||
| ChEBI | |||
| ChemSpider | |||
| 384 | |||
PubChem CID
|
|||
| |||
| |||
| Properties | |||
| H4OSi | |||
| Molar mass | 48.116 g·mol−1 | ||
| Appearance | Colorless liquid | ||
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
| |||
Silanol, also known as silyl alcohol, is a chemical with formula SiH3OH. It is the simplest silicon alcohol, and is a heavy, volatile, colorless, flammable liquid. At room temperature it is a polar liquid.
Silanol burns in air forming silicon dioxide and water:
- 2 SiH3OH + 3 O2 → 2 SiO2 + 4 H2O
Silanols are compounds containing silicon atoms to which hydroxyl substituents bond directly. They are similar to alcohols just as silanes are similar to alkanes.
When the hydroxyl group is principal, silanols are named by adding the suffix –ol to their mother name. If the hydroxyl group is not the principal one, silanols are named by using the prefix hydroxyl- according to the substitutive nomenclature. These rules are almost the same as those for alcohols, with the exception that silane is used as the mother hydride.
History
Silanols were first synthesized in 1871 by Albert Ladenburg. The first example was triethylsilanol. At that time, they were called silicols, a word that he coined.
Synthesis
Silanols are generally synthesized by hydrolysis of halosilanes, alkoxysilanes, or aminosilanes; by oxidation of hydrosilanes; or by hydrolysis of arylsilanes in the presence of a strong acid.
Properties
Silanols are generally dehydrated very easily, yielding disiloxanes in the presence of acid, base, or even heat. Because of this property of self-condensation, the synthesis and isolation of silanols are difficult.
Silanols have hydroxy substituents, and so they have hydrogen bonding to each other in solution and even in crystals.
Silanols can also be crosslinked using borax, or boric acid, to form 3-dimensional silicon gels.
Silanols exist not only as chemical compounds but also on the surface of silica. From the viewpoint of organometallic chemistry, silica can be considered as an enormous ligand, and it is used as support for catalysts of many reactions. In chromatography, derivitization of accessible silanol groups in a bonded stationary phase with trimethylsilyl groups is referred to as endcapping.