Crystal structure and thermodynamic properties of sodium d-gluconate Na[d-C6H11O7](s)

The sodium d-gluconate Na[d-C6H11O7](s) has been synthesized and characterized by elemental analysis and X-ray crystallography. X-ray single-crystal analysis reveals that the compound exhibits an obvious chelate property of d-gluconate anions to sodium cation, and the latter is coordinated to six d-gluconate anions. The lattice potential energy of the compound and ionic volume of the d-gluconate anion are obtained from crystallographic data. In accordance with law of Hess, a reasonable thermochemical cycle is designed and the standard molar enthalpy of formation of the compound Na[d-C6H11O7](s) is determined to be -(1472.68 +/- 0.48) kJ mol(-1) by use of an isoperibol solution-reaction calorimeter. Molar enthalpies of dissolution of Na[d-C6H11O7](s) at various molalities are measured at T = 298.15 K in the double-distilled water. According to Pitzer's electrolyte solution theory, molar enthalpy of dissolution of the title compound at infinite dilution is determined to be (23.783 +/- 0.128) kJ mol(-1).