The Sr-poor part of the Sr–{Pd,Pt}–{Si,Ge} systems: Phase equilibria and crystal structure of ternary phases.

Phase relations have been established by electron probe microanalysis (EPMA) and X-ray powder diffraction (XPD) for the Sr-poor part of four ternary systems: Sr–{Pd,Pt}–Si at 900 °C and Sr–{Pd,Pt}–Ge at 700 °C. In the Sr–Pd–Si system the formation of the silicide SrPdSi 3 (BaNiSn 3 -type) was confirmed and a small homogeneity region was found. Furthermore, two novel compounds were detected and their crystal structure was refined from X-ray powder patterns: SrPd 0.3 Si 1.7 (AlB 2 -type) and SrPd 5.9 Si 6.1 (own-type). In the Sr–Pt–Si ternary system a novel compound with AlB 2 -type was discovered (SrPt 0.3 Si 1.7 ), whereas SrPtSi 3 with the BaNiSn 3 -type was confirmed. Two more compounds were detected by EPMA, but their crystal structure remains unknown. In the Sr–{Pd,Pt}–Ge systems no new compounds were observed, but the existence of SrPdGe 3 and SrPtGe 3 (both adopt the BaNiSn 3 structure type), and SrPt 4 Ge 12 , crystallizing in the LaFe 4 Sb 12 structure type, was corroborated. For selected ternary silicides the electronic structure was evaluated by DFT calculations. [ABSTRACT FROM AUTHOR]