The Crystal Structures of Mn(ReO4)2·2H2O and of the Anhydrous PerrhenatesM(ReO4)2of Divalent Manganese, Cobalt, Nickel, and Zinc

Mn(ReO{sub 4}){sub 2}{center_dot}2H{sub 2}O (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}, {beta} = 110.87(4){degree}, Z = 2, calculated density D{sub x} = 4.40 g/cm{sup 3}. Chains of interconnected ReO{sub 4}-tetrahedra and MnO{sub 4}(OH{sub 2}){sub 2}-octahedra run parallel [0 1 0]. The AC-susceptibility ({mu}{sub eff} = 5.7 {mu}{sub B}) 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(ReO{sub 4}){sub 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), D{sub x} (g/cm{sup 3}) = 5.11 (Mn), 5.36 (Co), 5.44 (Ni), 5.33 (Zn). The structure is topologically equivalent to that of {beta}-Zr(MoO{sub 4}){sub 2}. M{sup 2+}O{sub 6}-octahedra are linked by ReO{sub 4}-tetrahedra to form layers which are not interconnected.