Me3SiOSiMe3

Me3SiOSiMe3, commonly known as hexamethyldisiloxane (HMDSO), is an organosilicon compound with the formula (CH3)3Si–O–Si(CH3)3. It consists of two trimethylsilyl groups bridged by a single oxygen atom, giving a nonpolar, volatile liquid at room temperature.

Physically, HMDSO is a colorless, low-polarity liquid that is soluble in many organic solvents. It is moisture sensitive and slowly hydrolyzes in the presence of water to yield trimethylsilanol (Me3SiOH) and siloxane byproducts, with the process capable of forming siloxane oligomers. Its volatility and relatively inert behavior under standard conditions make it a convenient reagent and solvent in certain organosilicon applications.

Applications of HMDSO include use as a solvent and as a precursor in the synthesis of silicon-oxide–containing materials. In microfabrication and surface chemistry, HMDSO is employed as a precursor for silicon oxide–based films in plasma-enhanced chemical vapor deposition (PECVD) and related processes, enabling deposition of SiO2- or SiOC-containing coatings. In polymer and organosilicon chemistry, HMDSO can serve as a siloxane source for introducing or building siloxane linkages and, in some protocols, can act as a source of trimethylsilyl groups, though more common silylating reagents are used for that purpose.

Safety and handling considerations include its flammability and potential irritation of skin, eyes, and the respiratory tract. It should be stored and used under dry, well-ventilated conditions, away from moisture and ignition sources.