Hexachlorodisilane is the inorganic compound with the chemical formula Si<sub>2</sub>Cl<sub>6</sub>. 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.
The molecule adopts a structure like ethane, 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:
Hexachlorodisilane is stable under air or nitrogen at temperatures of at least up to 400ðC for several hours, but decomposes to dodecachloroneopentasilane and silicon tetrachloride in presence of Lewis bases even at room temperature.
This conversion is useful in making silicon-based components of use in semiconducting devices including photovoltaic cells.
The compound is also useful reagent for the deoxygenation reactions, such as this general process involving a phosphine oxide: