A relationship has been derived between the activation energies E(a) of low-temperature non-autocatalyzed thermolysis of nitroparaffins and their oxygen balances. An analogous relationship has also been found for pre-exponents of log A of this thermolysis. The direct relationship existing between E(a) values and the impact sensitivity of the nitrocompounds in a condensed state is confirmed by the first relationship. From these two relationships, the molecular-structural dependences of the thermal reactivity of nitroparaffins in both gaseous and liquid states are discussed. For the thermolysis of mononitromethane in the liquid state, primary homolytic pseudo-monomolecular fragmentation decomposition is hypothesized.