Pulsed NMR study of proton motions in uranium trioxide hydrates

Pure samples of UO 2(OH) 2·H 2O, β-UO 2(OH) 2, and “α-UO 3·0.85H 2O” have been synthesized. Pulsed NMR data from a wide temperature range have been interpreted in terms of structural features and proton motions for all three materials. Two types of water molecule reorientation have been observed in UO 2(OH) 2·H 2O and characterized in terms of activation energies and correlation times for the motions (Motion A: T c = 2.2 ± 0.5 × 10 −15 sec, E A = 29.0 ± 4 kJ mole −1; Motion B: T c = 4 ± 0.5 × 10 −13 sec, E A = 31.2 ± 4 kJ mole −1).