Hexachlorodisilane

Hexachlorodisilane
Names
	IUPAC name Hexachlorodisilane
	Other names Perchlorodisilane
Identifiers
CAS Number	13465-77-5 ;
3D model (JSmol)	Interactive image;
ChemSpider	75334;
ECHA InfoCard	100.033.353
EC Number	236-704-1;
PubChem CID	83497;
UNII	9Z754456JM ;
CompTox Dashboard (EPA)	DTXSID0065488 ;
	InChI InChI=1S/Cl6Si2/c1-7(2,3)8(4,5)6 Key: LXEXBJXDGVGRAR-UHFFFAOYSA-N;
	SMILES [Si]([Si](Cl)(Cl)Cl)(Cl)(Cl)Cl;
Properties
Chemical formula	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). Infobox references

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.

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

References

^ ^a ^b 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.
^ 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

[Simmler-1] Simmler, W. "Silicon Compounds, Inorganic", Ullmann's Encyclopedia of Industrial Chemistry, Weinheim: Wiley-VCH. doi:10.1002/14356007.a24_001

[2] T.L. Cottrell, "The Strengths of Chemical Bonds," 2nd ed., Butterworths, London, 1958

[3] 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.

[4] 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

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