Nuclear magnetic resonance of29Si is used to study structural properties of porous silicon and siloxene. Evidence for changes in the chemical shift of porous silicon due to quantum confinement could not be observed. A hydride phase exhibiting a chemical shift of −75 ppm versus tetramethyl silane (TMS) is found in both porous silicon and siloxene. In as-prepared Wo¨hler siloxene, a chemical shift of −83 ppm versus TMS is assigned to threefold coordinated Si atoms forming a planar polysilane. ©1997 American Institute of Physics.