Structural Determination and Magnetic Properties of a New Orthorhombic Chromium Seleno Stannate, Cr 2Sn 3Se 7

Abstract

Since the discovery of a monoclinic phase Cr 2Sn 3Se 7, it has been found that, for the same composition, an orthorhombic phase exists. It is described in the Pnma space group with a = 23.097(1) Å, b = 3.8307(2) Å, and c = 12.5414(6) Å. The structure, refined to a reliability factor R F = 2.4%, is built upon [M 6Se 14] 1 ∞ blocks ( M = Cr(III) and Sn(IV)) defining 2,4 tunnels occupied by Sn(II) atoms in bicapped trigonal prisms. The orthorhombic Cr 2Sn 3Se 7 structure differs from the monoclinic one through the occurrence of [ M 6Se 14] 1 ∞ blocks instead of [ MSe 2] 2 ∞ layers. The magnetic susceptibility variation versus the applied magnetic field suggests a spin glass or a superparamagnetism behavior at low temperature.