Hexachlorodisilane is the inorganic compound with the chemical formula Si2Cl6.[1] 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.
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| Names | |
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| IUPAC name Hexachlorodisilane | |
| Other names Perchlorodisilane | |
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| ChemSpider | |
| ECHA InfoCard | 100.033.353 |
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| Properties | |
| Si2Cl6 | |
| Molar mass | 268.88 g/mol |
| Appearance | Colorless liquid |
| Melting point | −1 °C (30 °F; 272 K) |
| Boiling point | 144 °C (291 °F; 417 K) |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
Structure and synthesis
The molecule adopts a structure like ethane, with a single Si-Si bond length of 233 pm.[2]
Hexachlorodisilane is produced in the chlorination of silicides such as e.g. calcium silicide. Idealized syntheses are as follows:[3]
- CaSi2 + 4 Cl2 → Si2Cl6 + CaCl2
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 in presence of Lewis bases even at room temperature.[4]
- 4 Si2Cl6 → 3 SiCl4 + Si5Cl12
This conversion is useful in making silicon-based components of use in semiconducting devices including photovoltaic cells.[1]
The compound is also useful reagent for the deoxygenation reactions, such as this general process involving a phosphine oxide:
- 2 Si2Cl6 + OPR3 → OSi2Cl6 + PR3