The Pd-Sn-Te system and its geological applications ― First results

摘要

Phase relations have been studied in the system Pd-Sn-Te at 400°C. Experimental results reveal the existence of two new ternary phases: X (Pd_(45)Sn_(16)Te_(39)), Y (Pd_(68)Sn_(10)Te_(21)). The X phase is monoclinic, space group P-2/m, with cell parameters: a = 8.661 A, b = 9.720 A, c = 7.687 A, β = 72.42°. Ternary phases form broad solid solutions. The following phase assemblages were found to be stable in the system at 400°C: SnTe + Te + PdTe_2, PdTe_2 + X_(ss) + SnTe, PdTe_2 + X_(ss) + Pd(Te,Sn)_(ss), Pd(Te,Sn)_(ss) + Pd_2(Sn,Te)_(ss) + X_(ss), Sn + SnTe + PdSn_2, PdSn_2 + SnTe + PdSn, PdSn + SnTe + Pd_3Sn_2 , Pd_3Sn_2 + SnTe + X_(ss), Pd_3Sn_2 + X_(ss) + Pd_2(Sn,Te)_(ss). The Pd(Te,Sn) phase, analogous to the mineral kotulskite, dissolves up to 13 at.% of Sn. The Pd_2(Sn,Te) phase known as paolovite in nature, dissolves up to 8 at.% of Te. The existence of ternary phases Pd73Sn_(10)Te_(17) and Pd_(71)Sn_7Te_(22) (El-Bogary and Schubert 1971) has not been confirmed. The ternary phases X and Y are expected to be found in nature, in association with known Pd-Te and Pd-Sn minerals.