hexamethyldisiloxane

Hexamethyldisiloxane, commonly abbreviated HMDSO, is an organosilicon compound with the formula (CH3)3Si–O–Si(CH3)3. It is a colorless, volatile liquid at room temperature and a member of the disiloxane family. The molecule consists of two trimethylsilyl groups linked by an oxygen atom; each silicon center adopts a tetrahedral coordination with three methyl substituents.

Production and availability: HMDSO is typically prepared by dehydration of two molecules of trimethylsilanol or by condensation routes used in silicone chemistry. It is widely available commercially as a chemical reagent and as a precursor for silicon-containing thin films.

Uses: HMDSO serves as a source of silicon and oxygen in deposition processes, notably chemical vapor deposition and plasma-enhanced CVD, where it is used to form silicon oxide (SiO2)-like films on substrates. It is also used as a silylating or protecting agent in organic and silicon chemistry and as a building block for silicone materials.

Handling and safety: HMDSO is flammable and can form combustible vapors; it should be used in well-ventilated areas and with appropriate precautions to avoid ignition sources. It may cause irritation to skin, eyes, and the respiratory tract; vapors should be avoided. Store in a cool, dry place in compatible containers.