Structural Properties and Charge Distribution of the Sodium Uranium, Neptunium, and Plutonium Ternary Oxides

A Combined X-ray Diffraction and XANES Study

Journal article (2016)

Authors

A.L. Smith RST/Reactor Physics and Nuclear Materials - AS , European Commission, University of Cambridge
Philippe M. Martin CEA Cadarache
Damien Prieur European Commission
Andreas C. Scheinost Helmholtz Zentrum Dresden Rossendorf
Philippe E. Raison European Commission
Anthony K. Cheetham University of Cambridge
R. Konings European Commission, RST/Reactor Physics and Nuclear Materials - AS
Research Group
RST/Reactor Physics and Nuclear Materials (AS) (TU Delft)
Copyright: © 2016 A.L. Smith, Philippe M. Martin, Damien Prieur, Andreas C. Scheinost, Philippe E. Raison, Anthony K. Cheetham, R. Konings
DOI
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https://doi.org/10.1021/acs.inorgchem.5b02476
More Info
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Published Date

2016

Language

English

Faculty

Applied Sciences

Department

RST/Radiation, Science and Technology

Research Group

RST/Reactor Physics and Nuclear Materials

Abstract

The charge distributions in α-Na2UO4, Na3NpO4, α-Na2NpO4, Na4NpO5, Na5NpO6, Na2PuO3, Na4PuO5, and Na5PuO6 are investigated in this work using X-ray absorption near-edge structure (XANES) spectroscopy at the U-L3, Np-L3, and Pu-L3 edges. In addition, a Rietveld refinement of monoclinic Na2PuO3, in space group C2/c, is reported for the first time, and the existence of the isostructural Na2NpO3 phase is revealed. In contrast to measurements in solution, the number of published XANES data for neptunium and plutonium solid phases with a valence state higher than IV is very limited. The present results cover a wide range of oxidation states, namely, IV to VII, and can serve as reference for future investigations. The sodium actinide series show a variety of local coordination geometries, and correlations between the shape of the XANES spectra and the local structural environments are discussed herein.