STRUCTURAL PHASE-TRANSITIONS IN BACEO3

High-resolution neutron powder diffraction data have been collected on the perovskite BaCeO3 in the temperature range 373 K to 1273 K. Structural phase transitions, from space group Pmcn to P4/mbm at 427 K, and P4/mbm to Pm3BARm at 1112 K, that had been inferred from a recent Raman spectroscopy study were not found to occur. In the temperature range investigated, BaCeO3 undergoes three structural phase transitions, Pmcn to Incn at 563 K, Incn to F3BAR2/n at 673 K and F3BAR2/n to Pm3BARm at 1173 K. Crystal structure refinements are reported in each of the four phases for a single temperature.