Chemical Properties
Hexachlorodisilane is a colourless liquid, it is highly sensitive to moisture, and when exposed to air or water, it readily reacts, making it essential to handle the compound in a controlled, moisture-free environment.
Physical properties
bp 144–145.5 °C; d 1.562 g/cm3.
Uses
Hexachlorodisilane can be used in deoxygenation and desulfurization of phosphine oxides, phosphine
sulfides, and amine oxides; reducing agent for nitro groups
and sulfur diimides.
Preparation
Hexachlorodisilane is prepared in the chlorination of silicides such as e.g. calcium silicide. Idealized syntheses are as follows:
CaSi2 + 4 Cl2 → Si2Cl6 + CaCl2
Reactions
Hexachlorodisilane is a versatile chemical reagent that can be used in the following chemical reactions
[1-2]:
(1) When hexachlorodisilane is heated with a catalytic amount of triphenylphosphine or triphenylarsine, it decomposes according to the equation nSi2Cl6 = nSiCl4 + (SiCl2)n. It does not react with trifluoromethylphosphine. Hexabromodisilane is also decomposed by trimethylamine.
(2) Hexachlorodisilane reacts with hydrogen chloride in the presence of pyridine, and the reaction formula is:
Si2Cl6 + 2HCl = 2SiCl4 + H2.
(3) Excess hydrogen bromide and hexachlorodisilane produce a mixture of hydrogen chloride and hydrogen bromide.
(4) Hexachlorodisilane reacts with methyl chloride in the presence of triphenylphosphine to produce a mixture of methyltrichlorosilane and silicon tetrachloride. When hexachlorodisilane and methyl bromide are heated together in the presence of triphenylphosphine, a mixture of methyl chloride and bromine is produced.
(5) Hexachlorodisiloxane reacts with sulfur trioxide to produce silicon dioxide, sulfur dioxide and hexachlorodisiloxane.
General Description
Hexachlorodisilane (HCDS) is a chlorosilane used as a precursor for producing disilanes. It is a dioxidizer that is used in the production of silicon films and silicon nitride based films.
Flammability and Explosibility
Non flammable
References
[1] H.J. EMELéUS; Muhammad T. Reaction of hexachlorodisilane with bases and alkyl halides[J]. Journal of Inorganic and Nuclear Chemistry, 1967. DOI:10.1016/0022-1902(67)80468-8.
[2] B. S. SURESH D. P. Preparation of Hexafluorodisilane and Reactions of Hexafluorodisilane and Hexachlorodisilane with Sulfur Trioxide[J]. ACS Applied Electronic Materials, 1985. DOI:10.1246/BCSJ.58.1867.
