Synthesis and Crystal Structure of Ba6Cu12Fe13S27

Abstract

The new phase Ba6Cu12Fe13S27, a new djerfisherite-like compound, has been prepared by solid state reaction of BaS3and CuFeS2at 1273 K. This compound crystallizes in the cubic system with space groupPm m(No. 221),Z=1, and cell constanta=1037.9(1) pm. The discrepancy indices of the single crystal structure refinement wereR=0.023 andRw=0.030. The structure was determined using three-dimensional single crystal X-ray diffraction data and consists of a three-dimensional cubic framework of edges and corners sharing Cu- and Fe-centered tetrahedra forming large interconnecting tunnels and octahedral cages; one iron atom and a Ba6S octahedron per crystallographic unit cell are located in the cages and the channels, respectively. Consequently, were found two different geometrical environments for the transition metal atoms. XPS analysis reveal the presence of one valence state for copper, Cu(I), whereas iron exists as Fe(II) and Fe(III).