Correlations between standard partial molal entropies ( S ̄j0) of aqueous mono-, di-, and trivalent ions at 25°C and 1 bar and effective electrostatic radii (re,j) calculated from the corresponding crystallographic radii (rx,j) have been constructed for coordination numbers from 4 to 12. These correlations permit estimates of S ̄j0 to include information from spectroscopic studies about ionic coordination in aqueous solution. As a consequence, values of S ̄j0 can be estimated for many more ions than previously possible. Close agreement between predicted and experimental data for tetravalent cations supports the validity and generality of this approach. Combined with the experimentally determined values of S ̄j0 used to generate the correlations, estimates of standard partial molal entropies at 25°C and 1 bar for over 130 mon-atomic aqueous ions of charges ranging from -3 to +6 provide a set of S ̄j0 values for 188 monatomic aqueous ions for use in geochemical calculations.
ASJC Scopus subject areas
- Geochemistry and Petrology