Ag, Cu, Hg, Pt, Sb and Te substitutions in the synthetic analogue of palladseite, Pd 17 Se 15 : an experimental mineralogical study

[摘要] The solubility of Ag, Cu, Hg, Pt, Sb and Te in the synthetic analogue of palladseite was experimentally studied at 350 °C.To document the impact of these elements on the palladseite crystal structure, Rietveld refinement analysis of experimentalproducts was performed. The synthetic Pd17Se15 dissolves at 400 °C 3.6, 6.4, 8.8, 9.7, 6.1 wt. % of Cu, Ag, Hg, Pt andTe, respectively. The solubility of Sb in synthetic Pd17Se15 is less than 0.03 wt. %. Three different types of incorporationof the above-mentioned elements to the palladseite structure have been observed. Ag, Cu and Hg occupy a position 3dof the Pm–3m space group, which was empty in the unsubstituted Pd17Se15. Consequently, Pd occupancy of adjacent[Pd(4)Se6] octahedron is reduced to 0.46 and 0.51 for Cu and Ag-bearing palladseite, respectively. Incorporation of Hgto the palladseite structure causes vacancy of this Pd(4) position. Pt partially substitutes Pd at the Pd(2) position (6f ),forming Pd0.41/Pt0.59 mix site showing square-planar coordination by Se atoms. Te atoms substitute for Se. The refinedunit-cell parameter increased from the initial value of a = 10.6074(1) Å for Pd17Se15 to 10.6680(1) Å for Te-bearingpalladseite. Incorporation of Cu, Ag and Hg to the palladseite causes significant changes of its powder X-ray diffractionpattern and hence can be detected by PXRD.

[学科分类] 自动化工程

[关键词] palladseite;Pd17Se15;powder X-ray diffraction;Rietveld method;substitutions