Herein, we report a new salt of a pyrophosphate-functionalized uranyl peroxide nanocluster {U(24)Pp(12)} (1) exhibiting Oh molecular symmetry both in the solid and solution. Study of the system yielding 1 across a wide range of pH by single-crystal X-ray diffraction, small-angle X-ray scattering, and a combination of traditional P-31 and diffusion-ordered spectroscopy (DOSY) NMR affords unprecedented insight into the amphoteric chemistry of this uranyl peroxide system. Key results include formation of a rare binary {U-24}center dot{U(24)Pp(12)} (3) system observed under alkaline conditions, and evidence of acid-promoted decomposition of {U(24)Pp(12)} (1) followed by spatial rearrangement and condensation of {U-4} building blocks into the {U(32)Pp(16)} (2) cluster. Furthermore, P-31 DOSY NMR measurements performed on saturated solutions containing crystalline {U(32)Pp(16)} show only trace amounts (similar to 2% relative abundance) of the intact form of this cluster, suggesting a complex interconversion of {U(24)Pp(12)}, {U(32)Pp(16)}, and {U(4)Pp(4-x)} ions.