Sodium trimethylsiloxide is an organosilicon compound with the formula NaOSi(CH3)3.

It is the sodium salt of the conjugate base derived from trimethylsilanol.

[1] A white solid, its molecular structure consists of a cluster with Na-O-Na linkages on the basis of closely related compounds.

Trimethylsiloxide is a lipophilic pseudohalide.

[3][4] It is a source of oxide dianion.