Unveiling the Stability and Kinetic Pathway from Plutonium Clusters to Colloidal PuO 2 Nanoparticles
Year: 2026
Type: article
Abstract: The solution stability of plutonium(IV) oxo-hydroxo clusters is a central issue in actinide chemistry, with broad implications for fundamental coordination chemistry, the nuclear fuel cycle, and environmental migration. In this work, we investigate the long-term evolution of the hexanuclear [Pu 6 O 4 (OH) 4 ] 12+ cluster stabilized by acetate ligands. Using ultraviolet–visible (UV–vis) absorption spectroscopy coupled with X-ray absorption (XAS) and small-angle X-ray scattering (SAXS) synchrotron techniques, we probed its structural transformation over nearly one year of aging. UV–vis and XAS analyses revealed a progressive loss of the molecular cluster signature accompanied by the emergence of low Pu–Pu coordination environments (CN = 5–6), characteristic of PuO 2 colloidal nanoparticles. In contrast, SAXS measurements indicated a gradual increase in the apparent particle diameter of up to 10–15 nm, which is inconsistent with the formation of compact 2–3 nm PuO 2 nanoparticles usually observed in aqueous solutions. The combined results most probably support a mechanism in which the hexameric cluster first converts into PuO 2 primary colloids, which subsequently assemble into larger aggregates without crystallographic coalescence.
Source: Inorganic Chemistry
Authors: Maëva Munoz, Christelle Tamain, Matthieu Virot, Simon Bayle, Sandrine Dourdain, Thomas Dumas, Pier Lorenzo Solari, Denis Menut, Valérie Vallet, Dominique Guillaumont
Institutions: Université de Montpellier, Commissariat à l'Énergie Atomique et aux Énergies Alternatives, École Nationale Supérieure de Chimie de Montpellier, Centre National de la Recherche Scientifique, Institut de Chimie Séparative de Marcoule, Synchrotron SOLEIL, Université de Lille, Laboratoire de Physique des Lasers, Atomes et Molécules
Language: English
Subfield: Inorganic Chemistry
Field: Chemistry
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7147179177