Tetramethyl orthosilicate

Tetramethyl orthosilicate is the chemical compound with the formula Si(OCH3)4. This molecule consists of four methyl groups attached to the hypothetical anion SiO44-. The basic properties are similar to the more popular tetraethyl orthosilicate, which is usually preferred because the product of hydrolysis, ethanol, is less toxic than methanol.

Tetramethyl orthosilicate hydrolyzes to SiO2:
 * Si(OCH3)4 +  2 H2O  →  SiO2  +  4 CH3OH

In organic synthesis, Si(OCH3)4 has been used to convert ketones and aldehydes to the corresponding ketals and acetals, respectively.

Safety
The hydrolysis of Si(OCH3)4 produces insoluble SiO2. Should this process occur in the eyes, vision would be impared.