Molecular surface electrostatic potentials V_S(r) (ESP) of seventeen nitramines have been calculated. As a criterion of the imbalance between the maximum positive, V_S,max and minimum negative, V_S,min, values of molecular surface electrostatic potentials their sum was derived and used as a new simple characteristic for ESPs-V_S,Σ. These V_S,Σ values have close relationships with the Arrhenius parameters, activation energy E_a and preexponent log A, of thermal decomposition of the nitramines studied. The correlation between the V_S,Σ values and heats of fusion of the nitramines studied is described. These findings suggested analyzing the physico-chemical behavior of the nitramine crystals during this decomposition; in this connection an investigation was carried out using isothermal thermogravimetry and scanning electron microscopy of thermally exposed crystals of cis-1, 3, 4, 6-tetranitrooctahydroimidazo-[4, 5-d]imidazole (sintering of its crystal surfaces), of β-1, 3, 5, 7-tetranitro-1, 3, 5, 7-tetrazocane (cracking of its crystals during β→δ transition) and of 2, 4, 6, 8, 10, 12-hexanitro-2, 4, 6, 8, 10, 12-hexaazaisowurtzitane. The results suggest a need to study the pre-decomposition states on thermal decomposition of the nitramines′ molecule′s crystals.