PROTON MAGNETIC RESONANCE STUDIES OF POLYCRYSTALLINE URANIUM OXIDES HYDRATES. III. UO4 2H20

The broad-line proton magnetic resonance spectrum of polycrystalline samples of the compound formulated empirically as UO4(2H2O) has been investigated in the temperature range 77 to 356 K. Analyses of the absorption line shapes, and their derivatives, at 77 K and 257, coupled with chemical analysis for peroxide oxygen, show that the compound is essentially the dihydrate of uranyl peroxide, UO2(O2).2H2O. The sample investigated contains about 15% of a second component, possibly a hydroperoxide, UO(OH)3(OOH), or hydroxy peroxide, UO(OH)2(O2).H2O. At temperatures between 125 and 210 K, the absorption of the OH protons in this component undergoes changes which are compatible with self diffusion. The apparent activation energy for the motion is 2 kcal. The two component formulation of the 'compound' accounts for most, if not all, of its complex chemical behavior. (Author)