Thermodynamic stability of Ca3TeO6 determined by a solid electrolyte EMF method

• Gibbs energy of formation of Ca3TeO6 experimentally determined for the first time.
• Oxygen concentration galvanic cells based on YSZ solid electrolyte were employed.
• In the Ca–Te–O system, Ca3TeO6 coexists with CaO and Te.

The standard thermodynamic properties of Ca3TeO6 were determined electrochemically utilizing fast O2− ion conducting solid electrolyte yttria-stabilized zirconia. The ternary phase was synthesized from the pure oxides CaO and TeO2 in excess of CaO. The electromotive force measurements were performed on two similar electrochemical cells of the type Te + CaO + Ca3TeO6|YSZ|O2, within the temperature range from 850 to 949 K. The standard Gibbs energy of formation for the ternary compound Ca3TeO6 was determined for the first time, based on the experimental data obtained.