Synthesis and crystal structures of transition metal(II) fluoridometallate(IV) hydrates of neptunium and plutonium: AIIMIVF₆∙3H₂O (AII = Mn, Zn; MIV = Np, Pu)

Transition metal(II) fluoridometallates(IV) AIIMIVF6∙3H2O (AII = Mn, Zn; MIV = Np, Pu) were synthesized from NpO2 or PuO2 and the respective transition metal chlorides from hydrofluoric acid under mild conditions. The olive-green (Np) or orange (Pu) compounds were obtained as single-crystals and the respective structures were determined by single-crystal X-ray diffraction. In the isotypic compounds, chains of edgesharing tricapped trigonal prismatic polyhedra, [MIVF8/2(H2O)1/1] ∞1, are present and an overall threedimensional network structure is observed in which the AII and MIV atoms are arranged according to the simple NaCl structure type. Within the respective U-Pu series of the Zn and Mn salts the cell volumes and the MIV−F distances decrease due to the actinoid contraction.