The paper specifies an unambiguous basic relationship between the published results of ab initio calculations of lattice energies,E_L,and heats of sublimation,ΔH_s,of individual energetic materials. In this relationship,the ΔH_s value has been replaced by heats of fusion,ΔH_m,tr. Thereby its unambiguity has been lost,and the similarity of details of molecular structure begins to be of decisive importance. The resulting partial relationships,together with the basic relationship,have been used for prediction of ΔH_s,and ΔH_m,tr values of technically attractive polynitro compounds.