Synthesis, Structural, and Electronic Properties of K4PuVIO2(CO3)3(cr): An Environmentally Relevant Plutonium Carbonate Complex.

The chemical properties of actinide materials are often predefined and described based on the data available for isostructural species. This is the case for potassium plutonyl (PuVI) carbonate, K4PuVIO2(CO3)3(cr), a complex relevant for nuclear technology and the environment, of which the crystallographic and thermodynamic properties of which are still lacking. We report here the synthesis and characterization of PuVI achieved by single-crystal X-ray diffraction analysis and high-energy-resolution fluorescence-detected X-ray absorption near-edge structure at the Pu M4-edge coupled with electronic structure calculations. The crystallographic properties of PuVI are compared with isostructural uranium (U) and neptunium (Np) compounds. Actinyl (AnVI) axial bond lengths, [O-AnVI-O]2+, are correlated between solid, K4AnVIO2(CO3)3(cr), and aqueous, [AnVIO2(CO3)3]4-(aq) species for the UVI-NpVI-PuVI series. The spectroscopic data are compared to KPuVO2CO3(cr) and PuIVO2(cr) to tackle the trend in the electronic structure of PuVI regarding the oxidation state changes and local structural modifications around the Pu atom.

Nanoscopic X-ray imaging and quantification of the iron cellular architecture within single fibroblasts of Friedreich's ataxia patients.

Friedreich's ataxia (FRDA) is a neurodegenerative disease characterized by an increase in intracytoplasmic iron concentration. Here the nanoscale iron distribution within single fibroblasts from FRDA patients was investigated using synchrotron-radiation-based nanoscopic X-ray fluorescence and X-ray in-line holography at the ID16A nano-imaging beamline of the ESRF. This unique probe was deployed to uncover the iron cellular two-dimensional architecture of freeze-dried FRDA fibroblasts. An unsurpassed absolute detection capability of 180 iron atoms within a 30 nm × 50 nm nanoscopic X-ray beam footprint was obtained using state-of-the-art X-ray focusing optics and a large-solid-angle detection system. Various micrometre-sized iron-rich organelles could be revealed for the first time, tentatively identified as endoplasmic reticulum, mitochondria and lysosomes. Also a multitude of nanoscopic iron hot-spots were observed in the cytosol, interpreted as chaperoned iron within the fibroblast's labile iron pool. These observations enable new hypotheses on the storage and trafficking of iron in the cell and ultimately to a better understanding of iron-storage diseases such as Friedreich's ataxia.

Polycapillary Optics Based Confocal Micro X-ray Fluorescence and X-ray Absorption Spectroscopy Setup at The European Synchrotron Radiation Facility Collaborative Research Group Dutch-Belgian Beamline, BM26A.

A novel plug-and-play setup based on polycapillary X-ray optics enables three-dimensional (3D) confocal X-ray fluorescence (XRF) and X-ray absorption spectroscopy down to 8 × 8 × 11 µm3 (17 keV) at the European Synchrotron Radiation Facility Collaborative Research Group Dutch-Belgian Beamline, BM26A. A complete description and analytical characterization is presented, together with two recently performed experimental cases. In Deep Earth diamond São Luiz-Frankfurt am Main 16, an olivine-rich inclusion was mapped with full 3D XRF elemental imaging. The preliminary tests on Iron Gall ink contained in an historical document, a letter from the court of King Philip II of Spain, reveal both the delicate nature of Iron Gall ink and the lack of Fe-Ni chemical bonding.