Examining Order–Disorder Structural Transition of Gd2Zr2–xCexO7 Using Synchrotron Techniques
Date
2025-03
Authors
Kaur, Khushveer
King, Graham
Grosvenor, Andrew
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Abstract
Depending on the radius ratio of A and B site cations, A2B2O7-type oxides can adopt different crystal structures, including the pyrochlore-, defect fluorite-, or bixbyite-type structures. Gd2Zr2O7 with a rGd3+/rZr4+ ratio of 1.46 is an example that exhibits a polymorphic transition between the pyrochlore- and defect fluorite-type structures. To delve deeper into these polymorphic transitions, Ce was introduced as a substitute in the B-site of Gd2Zr2O7. Gd2Zr2–xCexO7 (0 ≤ x ≤ 2) was synthesized using a coprecipitation method and annealed at 1400 °C. Previous investigations yielded disparate results regarding the structures adopted due to the challenge of detecting the low-intensity superstructural peaks associated with the pyrochlore and bixbyite structures using conventional lab-based X-ray diffraction (XRD) instruments. Utilizing synchrotron XRD with a high signal/noise ratio resolves these contradictions and aids in the structure analysis for Gd2Zr2–xCexO7. Based on synchrotron XRD data, a combination of defect fluorite and pyrochlore phases was observed for x = 0–0.25, the defect fluorite structure was adopted when x = 0.5–1.75, and the bixbyite structure was observed when x = 2. Ce L3 and Zr K-edge X-ray absorption near edge spectroscopy (XANES) spectra revealed that both cations were present in 4+ oxidation states.
Description
This document is the unedited Author’s version of a Submitted Work that was subsequently accepted for publication in ACS Chemical Neuroscience copyright © 2025 American Chemical Society after peer review. To access the final edited and published work see https://doi.org/10.1021/acs.inorgchem.4c04795
Published version is linked at: https://doi.org/10.1021/acs.inorgchem.4c04795
Keywords
Cations, Chemical structure, Crystal structure, Defects, Diffraction
Citation
Kaur, K., King, G., & Grosvenor, A. P. (2025). Examining Order–Disorder Structural Transition of Gd2Zr2–x Ce x O7 Using Synchrotron Techniques. Inorganic Chemistry, 64(12), 5913–5922. https://doi.org/10.1021/acs.inorgchem.4c04795
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DOI
https://doi.org/10.1021/acs.inorgchem.4c04795