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Updated: Oct 1, 2025

Preparation, Purification, and Characterization of Lanthanide Complexes for Use as Contrast Agents for Magnetic Resonance Imaging
Published on: July 21, 2011
Effective coordination numbers from EXAFS: general approaches for lanthanide and actinide dioxides
Anna Romanchuk1, Alexander Trigub1, Tatiana Plakhova1
1Department of Chemistry, Lomonosov Moscow State University, Leninskie Gory 1, Bld. 3, Moscow 119991, Russian Federation.
Extended X-ray absorption fine structure (EXAFS) analysis reveals structural similarities in actinide dioxide nanoparticles (NPs). A new core-shell model accurately describes NP structure variations with decreasing size.
Area of Science:
- Materials Science
- Nuclear Chemistry
- Nanotechnology
Background:
- Extended X-ray absorption fine structure (EXAFS) is crucial for characterizing radioactive and nuclear materials.
- Interpreting EXAFS data for actinide nanoparticles (NPs) has been a subject of ongoing discussion.
- Understanding NP structure is vital for nuclear material applications.
Purpose of the Study:
- To compare new experimental data for PuO2 and CeO2 NPs with existing data on actinide dioxide (AnO2) NPs.
- To refine the interpretation of EXAFS structural data for AnO2 NPs.
- To propose and validate a new structural model for NPs.
Main Methods:
- Experimental EXAFS data collection for PuO2 and CeO2 NPs of varying sizes.
- Comparison of experimental data with published EXAFS data for other AnO2 NPs (ThO2, UO2).
- Development and application of a core-shell model with effective coordination number calculations.
Main Results:
- PuO2, CeO2, ThO2, and UO2 NPs exhibit similar structural behaviors.
- ThO2 NPs show a more disordered and partly amorphous structure compared to others.
- The proposed core-shell model effectively explains structural variations related to NP size.
Conclusions:
- EXAFS is a reliable method for AnO2 NP structural characterization.
- A core-shell model provides an excellent fit for describing size-dependent structural changes in NPs.
- This study clarifies EXAFS interpretation for actinide NPs.
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