Accurate or Fast Prediction of Solid-State Formation Enthalpies Using Standard Sublimation Enthalpies Derived From Geometrical Fragments

In view of its success in predicting sublimation enthalpies of molecular crystals near triple point conditions [ Ind. Eng. Chem. Res. 2012, 51, 2814], the geometrical fragment (GF) approach is presently used to estimate standard values Δ sub H 0 adjusted to the reference temperature of 298.15 K. The resulting GF 0 scheme is fitted against theoretically confirmed Δ sub H 0 data for 185 high nitrogen compounds and validated using organic compounds not used in the fitting process. It is subsequently used to predict the solid-state formation enthalpy Δ f H 0 (cr) of 40 energetic materials, combined with either correlated ab initio methods or simple models to estimate the gas-phase contribution. The combination of GF 0 with ab initio data yields Δ f H 0 (cr) values with state-of-the-art accuracy. Combined with the simple atom pair contribution model, this procedure predicts Δ f H 0 (cr) with better accuracy and stronger physical grounds than alternative low-cost methods.