In pursuit of the rhabdophane crystal structure: from the hydrated monoclinic LnPO4.0.667H2O to the hexagonal LnPO4 (Ln = Nd, Sm, Gd, Eu and Dy)

The dehydration process of the rhabdophane SmPO4.0.667H2O was studied over combination of in situ high resolution synchrotron powder diffraction and TGA techniques, a first dehydration was identified around 80 °C leading to the formation of SmPO4.0.5H2O (Monoclinic, C2). Then above 220 °C, the anhydrous form of the rhabdophane SmPO4 was stabilized and crystallizes in the hexagonal P3121 space group.217