The reaction of tetrakis(chloromethyl)silane, Si(CH2Cl)(4), with sodium azide afforded tetrakis(azidomethyl)silane (sila-pentaerythrityl tetraazide, Si(CH2N3)(4) (1b)). Nitration of tetrakis(hydroxymethyl)silane, Si(CH2OH)(4), with nitric acid resulted in the formation of tetrakis(nitratomethyl)silane (sila-pentaerythritol tetranitrate, Si(CH2ONO2)(4) (2b)). Compounds 1b and 2b are extremely shock-sensitive materials and very difficult to handle. Spectroscopic data were obtained as good as sensitivity and safety allowed for umambiguous identification. Quantum chemical calculations (DFT) of the C/Si pairs C(CH2OH)(4)/Si(CH2OH)(4), 1a/1b, and 2a/2b regarding the structures and electronic populations were performed.