Thermochemistry of potassium strontium tetraborate decahydrate

The enthalpies of solution of K2Sr[B4O5(OH)4]2·10H2O(cr) in approximately 1 mol dm−3 aqueous hydrochloric acid and of SrCl2·6H2O(cr) in aqueous solution (hydrochloric acid + boric acid + potassium chloride) were measured by solution calorimetry. From these results and other data, the standard molar enthalpy of formation image of K2Sr[B4O5(OH)4]2·10H2O(cr) has been derived to be −(10904.47 ± 6.46) kJ mol−1 at 298.15 K. According to a group contribution method, the standard molar Gibbs free energy image and the standard molar entropy image of K2Sr[B4O5(OH)4]2·10H2O(cr) were also calculated to be −9690.78 kJ mol−1 and 858.31 J K−1 mol−1 at 298.15 K.