The thermodynamic properties of Sr-Pb alloys were determined by electromotive force (emf) measurements. A Sr(s)vertical bar CaF2-SrF2 vertical bar Sr(in Pb) electrochemical cell was used to measure emf values at 773-1073 K for Sr-Pb alloys at mole fractions x(sr) = 0.07-0.59. These emf measurements were used to determine thermodynamic properties of Sr-Pb alloys, including activity, partial molar entropy, and partial molar enthalpy. At 873 K, activity values of Sr in Pb were as low as a(sr) = 1.72 x 10(-9) at mole fraction x(sr) = 0.07, implying strong atomic interactions between Sr and Pb. Phase transition temperatures of Sr-Pb alloys, observed during emf measurements, were corroborated by thermal analysis (0.07 <= x(sr) <= 0.34) by differential scanning calorimetry (DSC), and the phase constituents of Sr-Pb alloys (0.07 <= x(sr) <= 0.75) were characterized using X-ray diffraction (XRD). Experimentally-determined thermodynamic properties were compared to the assessed thermodynamic properties of the Sr-Pb system, confirming the phase transition temperatures and highlighting discrepancies in solution properties (activity and excess Gibbs energy). (C) The Author(s) 2018. Published by ECS.