A single crystal X-ray study of the fluorite-related “Solid solutions” of CeO2-YO1.5

Abstract

A study of the (1 - δ)CeO2 · δYO1.5 solid solution has been undertaken to understand the origin of the two-phase region that occurs between the fluorite-type, 0-∼50 mole% YO1.5, and C-type, ∼73-100 mole% YO1.5, solid solutions. Single crystal X-ray diffraction data have been collected at 49.7, 73.0, and 79.8 mole% YO1.5(cubic, Ia3̄, a = 10.757(2), 10.698(4), 10.678(3) Å, Z = 32) and the structures refined to R1 = 0.0841, 0.0146, and 0.0202 for 29, 25, and 72 independent reflections, respectively. The deviations from the ideal fluorite structure were examined and an apparent discontinuity observed for the metal atom shift allowed by Ia3̄ symmetry. Previously suggested metal atom ordering was not observed in the C-type structure. Models have been proposed to understand the limiting compositions of the fluorite-type and C-type solid solutions. Show more