In this work, thermodynamic properties of antimony saturated AgSbTe2 (Ag0.22Sb0.28Te0.50) and silver saturated SbxTe1-x (Ag0.08Sb0.49Te0.43) have been determined by solid state EMF technique with Ag+ ion conducting beta ''-alumina electrolyte, for the first time. The measurements were done by electrochemical cells of type: (-)Pt, AS vertical bar beta ''-alumina vertical bar Sb2Te3 + Ag2Te + SbxTe1-x, Re, Pt(+) Over the temperature range 566 <= T/K <= 620.5 and (-)Pt, Ag vertical bar beta ''-alumina vertical bar AgSbTe2 + Ag2Te + SbxTe1-x, Re, Pt(+) Over the temperature range 620.5 <= T/K <= 710. The phase transition temperature, where Sb2Te3 and Ag2Te form AgSbTe2 at 101.3 kPa pressure, was found to be T = 620.5 K. Standard thermodynamic quantities of SbxTe1-x and AgSbTe2 were calculated from the results obtained as well as Gibbs energies of formation as linear functions of temperature. Each test electrode, containing 3 phases in equilibrium, was synthetized separately inside an evacuated quartz glass ampoule and quenched into ice water. The contents of the test electrodes were confirmed by SEM-EDS analysis. Also, the average solubility of substances in the test electrodes was calculated from the SEM-EDS data obtained. The parasitic thermovoltage involved with the measured EMF was determined by symmetrical cell arrangement and compensated from the experimental values. (C) 2015 Elsevier Ltd. MI rights reserved.