Pure powdered compounds with a general formula ThEr(SiO)(PO) belonging to the zircon-xenotime family were successfully synthesized under hydrothermal conditions (250 °C, 7 days) as recently reported for the preparation of coffinite. Therefore, a thorough, combined PXRD, EDX, EXAFS, Raman, and FTIR analysis showed the formation of a solid solution in agreement with Vegard's law. Moreover, the examination of the local structure shows that the Th-O distances remain close to those found in ThSiO, whereas the Er-O distances show a significant decrease from 2.38(14) to 2.34(7) Å when increasing the erbium content from x = 0.2 to x = 1. The variation of the local structure also affects the PO groups that are surely distorted in the structure.

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We explored the use of selected layered double hydroxides (LDHs) of different compositions and obtained by means of different routes (i.e., coprecipitation, anionic exchange and reconstruction) as iodine/iodate adsorbents. The influence of speciation (iodide vs. iodate) on iodine uptake was rather strong, resulting in much lower iodide incorporation. The Fourier transform of iodine K X-ray absorption edge data (EXAFS) of all iodate-LDHs showed a single I-O scattering path of 1.8 Å . Thermal stability and leaching experiments showed that the incorporated iodate and iodide were rather loosely bound in the interlayer space and were easily released under heating to 180°C and leaching with Milli-Q water and brine solution.

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