Structure and magnetic behavior of the Na2NiInF7 weberite

Abstract The indium weberite Na 2 NiInF 7 has been synthesized in the form of single crystals. The symmetry of the unit cell is orthorhombic: a = 7.356(1)A, b = 10.334(2)A, and c = 7.5231(1)A, with space group Pmnb , Z = 4. The structure has been determined using 831 independent reflections ( R = 0.026, R w = 0.017). It is isostructural with Na 2 CuCrF 7 and Na 2 CuInF 7 . Parallel [NiF 5 ] 3 n − n octahedra chains run along the [100] axis separated by In atoms with octahedral coordination (InF = 2.083 A) with a seventh further atom at 2.730 A. The sodium atoms are 7- and 8-coordinated. The expected one-dimensional magnetic behavior has been confirmed, with a 3D-ordering temperature T N = 9 K. Below this temperature, a weak ferromagnetic component is observed.