The molecular topology of uranium(VI) bonding to iron and aluminium oxyhydroxide nanoclusters revisited by EXAFS spectroscopy

Applying a novel approach to the spectral analysis of Extended X-ray Absorption Fine Structure (EXAFS) we were able to derive an advanced 3-D structural model of the uranyl sorption complex on hydrated carbonate-free surfaces of aluminum(III) and iron(III) oxyhydroxide nanoclusters. The calculated molecular model fits the EXAFS data consistently up to a radial sphere of 4.5 Å around the uranium absorber. Being unaware of the physicochemical reasons for the specific complex topology characterized by a slightly tilted and distorted geometry, alternative ideas of EXAFS interpretation are discussed.