A new look at the structural properties of trisodium uranate Na3UO4

The crystal structure of the trisodium uranate, which forms following the interaction between sodium and hyperstoichiometric urania, has been solved for the first time using powder X-ray and neutron diffraction, X-ray Absorption Near-Edge Structure spectroscopy, and solid state 23Na Multi-Quantum Magic Angle Spinning Nuclear Magnetic Resonance. The compound, isostructural with Na3BiO4, has a monoclinic symmetry, in space group P2~c. Moreover, it has been shown that this structure can accommodate some cationic disorder, with up to 16(2)% sodium on the uranium site, corresponding to the composition -Na3(U1−x,Nax)O4 (0