A series of analogous nitratomethyl compounds of carbon and silicon of the formula types Me3EICH2ONO2 (1a/1b), Me2EI(CH2ONO2)(2) (2a/2b), MeEI(CH2ONO2)(3) (3a/3b), (CH2)(4)EI(CH2ONO2)(2) (4a/4b), and (CH2)(5)EI(CH2ONO2)(2) (5a/5b) were synthesized [El = C (a), Si (b); (CH2)(4)EI = (sila)cyclopentane-1,1-diy1; (CH2)(5)EI = (sila)cyclohexane-1,1-diy1]. All compounds were characterized by using NMR, IR, and Raman spectroscopy and mass spectrometry. In addition, the crystal structures of Me2C(CH2ONO2)(2) (2a), (CH2)(4)C(CH2ONO2)(2) (4a), Me2Si(CH2ONO2)(2) (2b), and (CH2)(5)Si(CH2ONO2)(2) (5b) were determined by single-crystal X-ray diffraction. The gas-phase structures of the C/Si analogues la and lb were determined by electron diffraction and compared with the results of quantum chemical calculations at different levels of theory. The thermal stabilities of the C/Si pairs la/lb-5a/5b were investigated by using DSC. In addition, their friction and impact sensitivities were measured with standard BAM methods. The extreme sensitivities of the silicon compounds lb 5b compared to those of the corresponding carbon analogues 1a 5a were discussed in terms of the structures of the C/Si analogues and possible geminal Si center dot center dot center dot O interactions.