CRYSTAL CHEMISTRY OF PHASES IN THE SYSTEM PD-SB-TE

Phases and phase relations and in the system Pd-Sb-Te were investigated at 1000°C, 800°C, and 600°C, using the sealed-capsule technique. The quenched run products were studied by reflecting microscopy, X-ray diffraction, and electron-microprobe analyser.

At 1000°C, palladium, Pd₂₀Sb₇, Pd₈Sb₃, stibiopalladinite (Pd₃₁Sb₁₂), and Pd₅Sb₂ are stable phases. At 800°C, sudburyite (PdSb), unnamed Pd₈Te₃, Pd₅Sb₃, and Pd₂₀(Sb,Te)₇ solid-solution. In addition, testibiopalladite (Pd₉Te₄), tellurantimony (Sb₂Te₃), unnamed PdSb₂, antimony, Pd₁₉Te₄, and two complete solid solutions between sudburyite and kotulskite, and unmaned PdSb₂ and merenskyite appear as stable phases at 600°C. All the phases in the system show solid solution mainly due to Sb and Te substitution, and their extent varies with temperature of formation.

In this study, synthetic PdSb₂, presumably an analogue of natural PdSb₂ was determined to be cubic with space group P213. Testibiopalladite, ideally PdSbTe, may be a member of the PdSb₂-Pd(Sb_0.32Te_0.68)₂ solid solution. Mineralogical properties for individual phases were compiled.