Determination of standard thermodynamic properties of Sb2O3 by a solid-oxide electrolyte EMF technique

A solid oxide electrolyte galvanic cell has been employed to obtain the thermodynamic properties of antimony trioxide Sb2O3 in the temperature range from 782 to 1080 K. Standard Gibbs energy of formation Delta(f)G degrees, the standard enthalpy of formation Delta H-f degrees(298) and standard entropy S degrees(298) were obtained by the electromotive force (EMF) method. The experimental procedure has been improved in order to increase the accuracy of the existing thermodynamic data. The obtained results have been compared to the data gathered in the previous studies. The standard Gibbs energies of formation obtained from multiple galvanic cells are linear functions of temperature as: Delta(f)G degrees/kJ mol(-1) = -679.82 + 0.235 T/K +/- 0.413 (782 - 903.65 K) both phases are solid Delta(f)G degrees/kJ mol(-1) = -739.53 + 0.301 T/K +/- 0.502 (903.65 - 929.15 K) Sb-liquid; Sb2O3-solid Delta(f)G degrees/kJ mol(-1) = -682.21 + 0.239 T/K +/- 0.419 (929.15 - 1080 K) both phases are liquid The standard enthalpy of formation Delta(f)G degrees(298) (-709.74/kJ mol(-1)) and standard entropy S degrees(295) (124.05/J(mol K)(-1)) were calculated for Sb2O3 using the measured values and c(p) functions given by previous studies. (C) 2014 Elsevier B.V. All rights reserved.