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

• DfGo, ΔfH°298 and S°298values for Sb2O3 have been determinedby the EMF technique.
• An improved experimental apparatus and data analysis method have been applied.

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 ΔfG°, the standard enthalpy of formation ΔfH°298 and standard entropy S°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:ΔfG°/kJ mol− 1 = − 679.82 + 0.235 T/K ± 0.413 (782 − 903.65 K) both phases are solidΔfG°/kJ mol− 1 = − 739.53 + 0.301 T/K ± 0.502 (903.65 − 929.15 K) Sb—liquid; Sb2O3—solidΔfG°/kJ mol− 1 = − 682.21 + 0.239 T/K ± 0.419 (929.15 − 1080 K) both phases are liquidThe standard enthalpy of formation ΔfH°298 (− 709.74/kJ mol− 1) and standard entropy S°298 (124.05/J(mol K)− 1) were calculated for Sb2O3 using the measured values and cp functions given by previous studies.