Alkaline-earth plumbates are important accessory phases in (Bi,Pb)-Sr-Ca-Cu-O (BSCCO) high temperature superconductor materials. Reliable values for standard enthalpies of formation (D f H o) of the plumbates are therefore an essential part of the BSCCO high temperature superconductor themodynamic data base. To obtain D f H o of SrPbO3 and Sr2PbO4, we measured the heats of solution of SrO, PbO2, SrPbO3, and Sr2PbO4 in 6M HCl by isoperibol solution calorimetry and derived the values of D f H o for the strontium plumbates using Hess cycles. The values obtained were D f H oSrPbO3 (298.15 K) = -949.3 3.5 kJ/mol and D f H oSr2PbO4 (298.15 K) = -1565.1 6.9 kJ/mol. In previous experiments, we measured total vapor pressures over SrPbO3 using Knudsen effusion vacuum thermogravimetry. In the present paper, these data were used for an independent derivation of D f H oSrPbO3(298.15 K) via a van't Hoff extrapolation, which yielded -945.8 7.5 kJ/mol, in reasonable agreement with the value obtained calorimetrically. Our determination of D f H oSr2PbO4(298.15) agrees well with a recently published value obtained from electrochemical measurements, but differs from earlier published calorimetric determinations.
Journal of Chemical Thermodynamics
enthalpy of formation, high temperature, knudsen effusion, PBO pressure, solution calorimetry, Sr<sub>2</sub>PbO<sub>4</sub>, SrPbO<sub>3</sub>, strontium plumbate, superconductor
, Cook, L.
and Wong-Ng, W.
Enthalpies of Formation of SrPbO<sub>3</sub> and Sr<sub>2</sub>PbO<sub>4</sub>, Journal of Chemical Thermodynamics
(Accessed June 5, 2023)