Resolving Confined Li Dynamics of Uranyl Peroxide Capsule U.

We obtained a kerosene-soluble form of the lithium salt [UO(O)(OH)] phase (Li-U), by adding cetyltrimethylammonium bromide surfactant to aqueous Li-U. Interestingly, its variable-temperature solution Li NMR spectroscopy resolves two narrowly spaced resonances down to -10 °C, which shift upfield with increasing temperature, and finally coalesce at temperatures > 85 °C. Comparison with solid-state NMR demonstrates that the Li dynamics in the Li-U-CTA phase involves only exchange between different local encapsulated environments.

U(IV) Aqueous Speciation from the Monomer to UO Nanoparticles: Two Levels of Control from Zwitterionic Glycine Ligands.

The fate of U(IV)O in the environment in a colloidal form and its dissolution and growth in controlled environments is influenced by organic ligation and redox processes, where both affect solubility, speciation, and transport. Here we investigate U(IV) aqueous speciation from pH 0 to 3 with the glycine (Gly) ligand, the smallest amino acid. We document evolution of the monomeric to the hexameric form from pH 0 to 3 via UV-vis spectroscopy and small-angle X-ray scattering (SAXS).