disiloxane

Disiloxane is a class of organosilicon compounds that contain two silicon atoms linked by an oxygen atom (Si-O-Si). The core motif is R3Si-O-SiR3, where R can be hydrogen, alkyl, or aryl groups. The simplest member is H3Si-O-SiH3, sometimes simply called disiloxane. A widely encountered derivative is hexamethyldisiloxane, (CH3)3Si-O-Si(CH3)3, often abbreviated HMDSO.

Formation and variants: Disiloxanes are typically prepared by condensation of silanols (R3Si–OH) or by hydrolysis of chlorosilanes (R3Si–Cl) followed by dehydration. By choosing different substituents on the silicon atoms, a family of compounds with varying volatility, solubility, and thermal stability can be obtained.

Properties: The Si–O–Si linkage provides flexibility and relatively high chemical stability. Physical state varies with structure: many disiloxanes and their derivatives are liquids at room temperature, with some being volatile, while bulkier or higher molecular weight members may be viscous liquids or solids. HMDSO is a volatile, colorless liquid under ambient conditions.

Applications: Disiloxanes serve as precursors to siloxane polymers and networks. Derivatives such as HMDSO are used as intermediates in organic and silicone chemistry and as precursors for silicon oxide films in processes like chemical vapor deposition and plasma deposition, contributing to coatings and microelectronics applications.

Safety: As with many organosilicon compounds, handling should follow standard laboratory safety practices, including adequate ventilation and avoidance of inhalation or skin contact.

See also: Siloxanes, Silanes, Hexamethyldisiloxane.