Synthesis and Structure of Ln₂(H₄IO₆)(I₂O₁₀)·H₃O·5 H₂O (Ln=Pr, Nd, Sm), a Lanthanide Periodate Diperiodate

Abstract

By slow evaporation of solutions containing Ln(ClO4)3 (Ln=Pr, Nd, Sm), H5IO6 and an excess of HClO4, crystals of the title compounds could be obtained. Their structures were determined by single‐crystal X‐ray diffraction. The compounds crystallize in the monoclinic crystal system, space group I2/a. They contain two types of periodate ions: octahedral H4IO6 groups and two crystallographically different I2O10 groups, which consist of two edge‐sharing octahedra. These anions coordinate to the cations as bridging groups yielding a three‐dimensional network. Together with some water of crystallization, a coordination number of 9 is achieved around the lanthanide ions with a tri‐capped trigonal prismatic geometry.