The O ion conductivity was measured in (Bi2O3)1-x(Pr6O11)x systems at temperatures ranging from ambient to 550C. At x = 0.05, the rhombohedral Bi1.35Pr0.65O3 structure was found to be stable at up to 550C. At higher concentrations, a mixture of rhombohedral and possibly monoclinic structures was observed. At x = 0.2, these became fully monoclinic. High-temperature X-ray powder diffraction confirmed the stability of the observed phases over the temperature range studied. The optimum ionic conductivity was found for the mixed phase, and a value of 0.0123S/cm was found for x = 0.15 at 450C.

N.M.Sammes, G.J.Gainsford: Solid State Ionics, 1993, 62[3-4], 179-84