Sodium silox is the name for an organosilicon compound that serves as a source of the siloxide anion [(CH3)3C]3SiO−.

Complexes of this bulky anionic ligand often adopt with low coordination numbers.

The sodium derivative, which has salt-like properties, is a cubane-type cluster.

Silox has a larger cone angle than C5Me5− and is a poorer donor.

For these reasons, silox anion forms highly unsaturated complexes.