Structural and thermochemical properties, and energetics of C8(NO2)8 and C20(NO2)4n (n = 0–4)

Density-functional-theory calculations, at the B3LYP level with the 6–31 G basis set, have been performed to investigate the structural and electronic properties of octanitrocubane, C8(NO2)8, and polynitrofullerenes of type C20(NO2)4n, with n = 0–4, in their ground states. Having determined their energetically optimized geometric structures, energetics, and vibrational frequencies, we have calculated the enthalpies of combustion and decomposition of these molecules. Extrapolating from the so-obtained data, we have also estimated, as a by-product, the enthalpy values of C20(NO2)20.