Ammonium Polyuranates: Old Dog, New Structural Tricks.

The crystal structure of ammonium polyuranates has been investigated. Powder X-ray diffraction (PXRD) has been employed to define single-phase samples within a series of synthesized compounds, which are further characterized by elemental analysis to ascertain the stoichiometry, revealing compositions of and . Analysis using extended X-ray absorption fine structure and vibrational spectroscopy has elucidated that both and possess a local structure similar to the metaschoepite─layered U(VI) oxohydroxide UO·2HO, but with HO and NH groups in the interlayers.

Uranium oxides structural transformation in human body liquids.

Uranium oxide microparticles ingestion is one of the potential sources of internal radiation doses to the humans at accidental or undesirable releases of radioactive materials. It is important to predict the obtained dose and possible biological effect of these microparticles by studying uranium oxides transformations in case of their ingestion or inhalation. Using a combination of methods, a complex examination of structural changes of uranium oxides in the range from UO to UO, UO and UO as well as before and after exposure of uranium oxides in simulated biological fluids: gastro-intestinal and lung-was carried out.

From EXAFS of reference compounds to U(VI) speciation in contaminated environments.

Understanding the speciation of technogenic uranium in natural systems is crucial for estimating U migration and bioavailability and for developing remediation strategies for contaminated territories. Reference EXAFS data of model laboratory-prepared uranium compounds (`standards') are necessary to analyze U-contaminated samples from nuclear legacy sites. To minimize errors associated with measurements on different synchrotrons, it is important not only to compare data obtained on environmentally contaminated samples with the literature but also with `standards' collected at the same beamline.