X-ray powder diffraction study of cesium ammonium hexachlorotellurate [Cs_(0.86)(NH_4)_(0.14)]_2TeCl_6

摘要

The crystal structure of cesium ammonium hexachlorotellurate [Cs_(0.86)(NH_4)_(0.14)]_2TeCl_6, has been determined using X-ray powder diffraction techniques. At room temperature, the title compound crystallizes in the cubic space group Fm3m, with a lattice parameter a= 10.470(17) A. The Rietveld refinement of the structure led to final confidence factors R_p=0.0338 and R_(wp)= 0.0487. The structure of [Cs_(0.86)(NH_4)_(0.14)]_2TeCl_6, belongs to the large family of K_2PtCl_6-related structures. The H atoms of the ammonium group are orientated with its apex toward Te atoms as seen in the related compound (NH_4)_2SiF_6. An IR spectroscopic study was performed to confirm the results of the diffraction method, notably concerning the presence of the ammonium group.