Hexachlorodisilane is the
inorganic compound
In chemistry, an inorganic compound is typically a chemical compound that lacks carbon–hydrogen bonds, that is, a compound that is not an organic compound. The study of inorganic compounds is a subfield of chemistry known as '' inorganic chemis ...
with the
chemical formula
In chemistry, a chemical formula is a way of presenting information about the chemical proportions of atoms that constitute a particular chemical compound or molecule, using chemical element symbols, numbers, and sometimes also other symbols, ...
Si
2Cl
6.
[Simmler, W. "Silicon Compounds, Inorganic", ''Ullmann's Encyclopedia of Industrial Chemistry'', Weinheim: Wiley-VCH. ] It is a colourless liquid that fumes in moist air. It has specialty applications in as a reagent and as a volatile precursor to silicon metal.
Structure and synthesis
The molecule adopts a structure like
ethane
Ethane ( , ) is an organic chemical compound with chemical formula . At standard temperature and pressure, ethane is a colorless, odorless gas. Like many hydrocarbons, ethane is isolated on an industrial scale from natural gas and as a petroc ...
, with a single Si-Si bond length of 233 pm.
Hexachlorodisilane is produced in the chlorination of silicides such as e.g. calcium silicide. Idealized syntheses are as follows:
:CaSi
2 + 4 Cl
2 → Si
2Cl
6 + CaCl
2
Reactions and uses
Hexachlorodisilane is stable under air or nitrogen at temperatures of at least up to 400°C for several hours, but decomposes to
dodecachloroneopentasilane and
silicon tetrachloride
Silicon tetrachloride or tetrachlorosilane is the inorganic compound with the formula SiCl4. It is a colourless volatile liquid that fumes in air. It is used to produce high purity silicon and silica for commercial applications.
Preparation
Silic ...
in presence of Lewis bases even at room temperature.
[Emeleus, H. J., and Muhammad Tufail. "Reaction of Hexachlorodisilane with Bases and Alkyl Halides." Journal of Inorganic and Nuclear Chemistry 29.8 (1967): 2081-084]
:4 Si
2Cl
6 → 3 SiCl
4 + Si
5Cl
12
This conversion is useful in making silicon-based components of use in semiconducting devices including photovoltaic cells.
The compound is also useful
reagent
In chemistry, a reagent ( ) or analytical reagent is a substance or compound added to a system to cause a chemical reaction, or test if one occurs. The terms ''reactant'' and ''reagent'' are often used interchangeably, but reactant specifies a ...
for the
deoxygenation
Deoxygenation is a chemical reaction involving the removal of oxygen atoms from a molecule. The term also refers to the removal of molecular oxygen (O2) from gases and solvents, a step in air-free technique and gas purifiers. As applied to orga ...
reactions, such as this general process involving a phosphine oxide:
:2 Si
2Cl
6 + OPR
3 → OSi
2Cl
6 + PR
3
References
Chlorosilanes
Chlorides