Hexachlorodisilane
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| Names | |
|---|---|
| IUPAC name
Hexachlorodisilane | |
| Other names
Perchlorodisilane | |
| Identifiers | |
3D model (JSmol) |
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| ChemSpider | |
| ECHA InfoCard | 100.033.353 |
| EC Number |
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PubChem CID |
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| UNII | |
CompTox Dashboard (EPA) |
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| Properties | |
| Si2Cl6 | |
| Molar mass | 268.88 g/mol |
| Appearance | Colorless liquid |
| Density | 1.562 g/cm3 (25 °C)[1] |
| 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).
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Hexachlorodisilane is the inorganic compound with the chemical formula Si2Cl6.[2] 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
[edit]The molecule adopts a structure like ethane, with a single Si-Si bond length of 233 pm.[3]
Hexachlorodisilane is produced in the chlorination of silicides such as e.g. calcium silicide. Idealized syntheses are as follows:[4]
- CaSi2 + 4 Cl2 → Si2Cl6 + CaCl2
A more selective synthesis is the decomposition of silicon tetrachloride to perchloropolysilanes via glow discharge, followed by rechlorination.[5] Higher homologues (i.e., the bromide and iodide) cannot be produced this way, requiring instead dephenylation (Friedel-Crafts ipso substitution) of hexaphenyldisilane by the appropriate acyl halide with a catalytic aluminum salt.[6]
Reactions and uses
[edit]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.[7]
- 4 Si2Cl6 → 3 SiCl4 + Si5Cl12
This conversion is useful in making silicon-based components of use in semiconducting devices including photovoltaic cells.[2]
The compound is also useful reagent for the deoxygenation reactions, such as this general process involving a phosphine oxide:
- Si2Cl6 + OPR3 → OSi2Cl6 + PR3
References
[edit]- ↑ "Hexachlorodisilane". Millipore Sigma. Properties (HTML selector #pdp-properties). Retrieved 17 August 2026.
- 1 2 Simmler, W. "Silicon Compounds, Inorganic", Ullmann's Encyclopedia of Industrial Chemistry, Weinheim: Wiley-VCH. doi:10.1002/14356007.a24_001
- ↑ T.L. Cottrell, "The Strengths of Chemical Bonds," 2nd ed., Butterworths, London, 1958
- ↑ Seo, E.S.M; Andreoli, M; Chiba, R (2003). "Silicon tetrachloride production by chlorination method using rice husk as raw material". Journal of Materials Processing Technology. 141 (3): 351. doi:10.1016/S0924-0136(03)00287-5.
- ↑ Molnar, Wolfgang; Lugstein, Alois; Wojcik, Tomasz; Pongratz, Peter; Auner, Norbert; Bauch, Christian; Bertagnolli, Emmerich (31 July 2012) [30 May 2012]. "Synthesis and electrical characterization of intrinsic and in situ doped Si nanowires using a novel precursor". Beilstein Journal of Nanotechnology. 3: 564–569. See also Schmeisser, Martin and Voss, Peter (December 1964) "Über das Siliciumdichlorid [SiCl2]x" (in German), Zeitschrift für anorganische und allgemeine Chemie, doi:10.1002/zaac.19643340108, as cited in Molnar et al.
- ↑ Berger, Matthias; Auner, Norbert; Bolte, Michael (20 October 2014) [7 July 2014]. "Hexabromo- and hexaiododisilane". Acta Crystallographica C: 1088–1091. doi:10.1107/S2053229614022992.
- ↑ 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