Probing the Long- and Short-Range Structural Chemistry in the C-Type Bixbyite Oxides Th0.40Nd0.48Ce0.12O1.76, Th0.47Nd0.43Ce0.10O1.785, and Th0.45Nd0.37Ce0.18O1.815 via Synchrotron X-ray Diffraction and Absorption Spectroscopy
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Summary
This summary is machine-generated.This study reveals how thorium, neodymium, and cerium oxide compounds form C-type bixbyite structures with oxygen vacancies. Nd³⁺ incorporation causes local bond contraction and lattice expansion, influencing overall structural chemistry.
Area Of Science
- Materials Science
- Solid-State Chemistry
- Crystallography
Background
- C-type bixbyite structures are complex oxides with potential applications.
- Understanding the interplay of cations and oxygen vacancies is crucial for materials design.
- Thorium, neodymium, and cerium oxides offer a unique system to study these interactions.
Purpose Of The Study
- To systematically examine the long- and short-range structural chemistry of Th-Nd-Ce-O compounds.
- To elucidate the role of oxygen vacancies and cation incorporation on structural properties.
- To correlate local chemical behavior with long-range structural characteristics.
Main Methods
- Synchrotron X-ray powder diffraction (S-PXRD) for long-range structure.
- High-energy resolution fluorescence detection X-ray absorption near edge (HERFD-XANES) for Ce and Nd oxidation states and local coordination.
- Extended X-ray absorption fine structure spectroscopy (EXAFS) for Th-O bond distances.
- Electronic structure calculations to support experimental findings.
Main Results
- Compounds form C-type bixbyite structures with disordered cations and oxygen vacancies.
- Cerium (Ce) exists as Ce⁴⁺ with local distortions, while Neodymium (Nd) exists as Nd³⁺, facilitating charge balance and oxygen defect formation.
- Increased Nd content leads to shorter Th-O and Th-Ce bond lengths, local bond contraction, enhanced Th cation valence, and overall lattice expansion.
Conclusions
- Oxygen defects induced by Nd³⁺ incorporation significantly influence local bond lengths and cation valence.
- The study highlights how variable short-range chemical behavior of dissimilar cations impacts the long-range structural chemistry of complex oxides.
- Findings provide insights into the structure-property relationships of mixed-metal oxides.
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