The crystal structures of Mn(ReO4)2·2H2O and of the anhydrous perrhenates M(ReO4)2 of divalent manganese, cobalt, nickel, and zinc

Mn(ReO4)2·2H2O (manganese(II)-perrhenate dihydrate) is analyzed by X-ray single-crystal diffraction and TG/DTA. Space group C2/m, a = 14.71(1) angstrom, b = 5.861(6) angstrom, c = 5.537(5) angstrom, β = 110.87(4)degree, Z = 2, calculated density Dx = 4.40 g/cm3. Chains of interconnected ReO4-tetrahedra and MnO4(OH2)2-octahedra run parallel [0 1 0]. The AC-susceptibility (μeff = 5.7 μB) is consistent with divalent Mn and heptavalent Re. Dehydration takes place in a single step at 150 C. Decomposition starts at 820 C. The dehydration product Mn(ReO4)2 and the isotypic anhydrous perrhenates of Co, Ni, Zn crystallize in space group P bar 3, Z = 1; a ranges from 5.67 (Ni) to 5.86 angstrom (Mn), c ranges from 6.07 (Mn) to 6.17 angstrom (Zn), Dx (g/cm3) = 5.11 (Mn), 5.36 (Co), 5.44 (Ni), 5.33 (Zn). The structure is topologically equivalent to that of β-Zr(MoO4)2. M2+O6-octahedra are linked by ReO4-tetrahedra to form layers which are not interconnected