A novel compound barium D-gluconate tetrahydrate, Ba[D-C6H11O7](2)center dot 4H2O, is synthesized and characterized by chemical analysis, elemental analysis, and X-ray crystallography. Single-crystal X-ray analysis reveals that the compound is formed by two D-gluconate anions, one barium (II) cation and four crystal water molecules. The compound exhibits an outstanding chelate property of D-gluconate anions to barium (II) cations, and the barium (II) cation is ten-coordinated and chelated by six D-gluconate anions. The molecules of the compound are further linked by intermolecular BaAO and OAHO interactions to form a 3D supramolecular architecture. The lattice potential energy and ionic volume of the anion are obtained from crystallographic data. In accordance with Hess' law, a reasonable thermochemical cycle is designed and the standard molar enthalpy of formation of Ba[D-C6H11O7] 2 4H2O(s) is calculated as DsHm [Ba[D-C6H11O7] 2.4H2O, s] = (4712.85 1.06) kJ. mol-1 by use of an isoperibol solution-reaction calorimeter. Molar enthalpies of dissolution of Ba[D-C6H11O7] 2 4H2O(s) at various molalities are measured at T = 298.15 K in the double-distilled water. According to the Pitzer theory, the molar enthalpy of dissolution of the title compound at infinite dilution is calculated to be DsH1m = (49.901 +/- 1.212) kJ center dot mol-1. The values of relative apparent molar enthalpies (appH), relative partial molar enthalpies of the solvent (H1) and the compound (H2) at different molalities m/(mol.kg-1) are derived from the experimental values of the enthalpies of dissolution of the compound. (C) 2013 Elsevier Ltd. All rights reserved.