Standard absolute entropies, SO298, from volume or density -: Part II.: Organic liquids and solids

The standard absolute entropies of many materials are unknown, which precludes a full understanding of their thermodynamic stabilities. We show, for both organic liquids and solids, that entropies are reliably linearly correlated with Volume per molecule, V-m (nm(3) per molecule) (or molar volume, M/rho (cm(3) mol(-1))); thus, permitting simple evaluation of standard entropies (J K-1 mol(-1)) at 298 K. The regression lines generally pass close to the origin, with formulae: For organic liquids: S(298)degrees(l) (J K-1 mol(-1)) = 1133(V-m (nm(3) per molecule)) + 44 or S(298)degrees (l) (J K-1 mol(-1)) = 1.881 [M/rho (cm(3) mol(-1))] + 44 For organic solids: S(298)degrees (s) (J K-1 mol(-1)) = 774(V-m (nm(3) per molecule)) + 57 or S(298)degrees (s) (J K-1 mol(-1)) = 1.285 [M/rho (cm(3) mol(-1))] + 57 These results complement similar studies (by ourselves and others) demonstrating linear entropy-volume correlations for ionic solids (including minerals, simple ionic solids and ionic hydrates and solvates), but are now-for the first time-demonstrated for organic materials. Part I of this series of papers [22] applies a similar analysis to ionic solids. (C) 2003 Elsevier B.V. All rights reserved.