Synthesis, Structures, and Characterization of MMnZrF7 (M = Tl, Rb, NH4, K) Fluorides: An Example of 7-Coordination of Divalent Manganese

摘要: Abstract A series of phases with formula M I MnZrF 7 (M = Tl, Rb, NH 4 , K) was synthesized and their crystal chemical characteristics were determined from X-ray powder diffraction data. The structures both Tl Rb representatives refined single Both fluorides are isostructural crystallize in the monoclinic system unit cell dimensions a 6.450(1) A, b 8.250(1) c 6.459(2) β 118.0(2)° 6.439(3) 8.218(2) 6.443(1) 117.9(2)° respectively, P 2 1 / m (No. 11) space group, Z 2. This structural type is built chains edge-shared alternated pentagonal bipyramids Mn 2+ Zr 4+ extending along [101] direction, that linked together by sharing corners to form (MnZrF ) n- n layers perpendicularly axis. Layers connected through apical fluorine atoms bipyramidal groups, into three-dimensional network delimiting pseudohexagonal tunnels parallel [010] within which monovalent cations located. Structural relationships KIn F β-KYb β-U 3 O 8 discussed.