The ternary Zr–Pt–Sb system

Abstract

The isothermal cross-section of the phase diagram of the ternary Zr–Pt–Sb system in the whole concentration range at 600 °C has been investigated by means of X-ray analysis. The samples were prepared by arc-melting of the pure elements under argon atmosphere with further annealing in evacuated silica tubes at 600 °C for 720 h followed by quenching in cold water. Five new compounds were discovered in this system: Zr 6PtSb 2 (Zr 6CoAl 2-type, P 6 ¯ 2 m , a = 7.797(2) Å, c = 3.716(2) Å), ZrPt 2− x Sb (MnCu 2Al-type, F m 3 ¯ m , a = 6.3205(7) Å), Zr 9Pt 9Sb 2 (Zr 9Pt 11-type, I4/ m, a = 10.4118(8) Å, c = 7.0250(8) Å), Zr 5PtSb 2 (tetragonal, a = 11.0721(8) Å, c = 5.5369(6) Å), and ∼Zr 2Pt 2Sb (unknown structure). The existence of two previously known compounds, Zr 5PtSb 3 (Hf 5CuSn 3-type, P6 3/ mcm, a = 8.634(2) Å, c = 5.805(2) Å) and Zr 3Pt 3Sb 4 (Y 3Au 3Sb 4-type, I 4 ¯ 3 d , a = 9.4205(8) Å), was confirmed. The homogeneity ranges were determined to be x = 0.4–0.6 for ZrPt 2− x Sb and x = 0.57–1.0 for Zr 5Pt x Sb 3.