Investigation of the phase diagrams of the systems R-Ni-Pb (R = Y, La, Ce, Dy) and crystal structures of the compounds R_4Ni_3Pb_4 (R = La, Ce, Pr) and R_5NiPb_3 (R = Y, La, Ce, Pr, Tb, Dy, Ho, Er, Tm, Lu)

摘要

The isothermal sections of the systems Y-Ni-Pb (at 870 K), La-Ni-Pb (at 670 K), Ce-Ni-Pb (at 670 K) and Dy-Ni-Pb (at 870 K) were constructed using X-ray phase analysis. Five ternary compounds were found in the Y-Ni-Pb system: YNiPb (TiNiSi structure type, space group Pnma, a = 0.71590(4) nm, b = 0.45176(2) nm, c = 0.77610(4) nm), Y_2Ni_2Pb (Mn_2AlB_2 structure type, space group Cmmm, a = 0.4019(1)nm, b= 1.4008(3)nm, c = 0.3679(l)nm), Y_5NiPb_3 (Hf_5CuSn_3 structure type, space group P6_3/mcm, a = 0.8991(1)nm, c = 0.66393(4) nm), Y_(12)Ni_6Pb (Sm_(12)Ni_6In structure type, space group Im3, a = 0.97149(2) nm) and Y_6Ni_(2.5)Pb_(0.5) (Ho_6Co_2Ga structure type, space group Immm, a = 0.9462(1) nm, b = 0.9605(1) nm, c = 0.9891(1) nm). The existence of the compounds La_4Ni_3Pb_4 (La_4Ni_3Pb_4 structure type, space group R3, a = 1.00367(7) nm, c = 0.95558(8) nm), La_5NiPb_3 (Hf_5CuSn_3 structure type, space group P6_3/mcm, a = 0.94867(4) nm, c = 0.69839(4) nm), La_(12)Ni_6Pb (Sm_(12)Ni_6In structure type, space group Im3, a = 1.0233(2) nm) in the La-Ni-Pb system and the compounds Ce_4Ni_3Pb_4 (La_4Ni_3Pb_4 structure type, space group R3, a = 0.9947(1) nm, c = 0.94604(9) nm), Ce_5NiPb_3 (Hf_5CuSn_3 structure type, space group P6_3/mcm, a = 0.93839(4) nm, c = 0.67922(4) nm) in the Ce-Ni-Pb system was determined. The existence of five ternary compounds DyNiPb (TiNiSi structure type, space group Pnma, a = 0.71485(5) nm, b = 0.45219(3) nm, c = 0.77481 (6) nm), Dy_2Ni_2Pb (Mn_2AlB_2 structure type, space group Cmmm, a = 0.4026(1)nm, b= 1.3994(4)nm, c = 0.3651(1)nm), Dy_5NiPb_3 (Hf_5CuSn_3 structure type, space group P6_3/mcm, a = 0.8956(1) nm, c = 0.65733(7) nm), Dy_(12)Ni_6Pb (Sm_(12)Ni_6In structure type, space group Im3, a = 0.9662(1) nm) and Dy_6Ni_(2.39)Pb_(0.55) (Ho_6Co_2Ga structure type, space group Immm, a = 0.93748(3) nm, b = 0.95427(3) nm, c = 0.98823(3) nm) in the Dy-Ni-Pb system was established. Additionally the existence of the compounds Pr_4Ni_3Pb_4 (La_4Ni_3Pb_4 structure type, space group R3, a = 0.9889(1) nm, c = 0.9417(1) nm), Pr_5NiPb_3 (Hf_5CuSn_3 structure type, space group P6_3/mcm, a = 0.9337(1) nm, c = 0.67927(6) nm), Tb_5NiPb_3 (Hf_5CuSn_3 structure type, space group P63/mcm, a = 0.90448(7) nm, c = 0.66101(3) nm), Ho_5NiPb_3 (Hf_5CuSn_3 structure type, space group P6_3/mcm, a = 0.89315(6) nm, c = 0.65649(2) nm), Er_5NiPb_3 (Hf_5CuSn_3 structure type, space group P6_3/mcm, a = 0.89065(7) nm, c = 0.65631(3) nm), Tm_5NiPb_3 (Hf_5CuSn_3 structure type, space group P6_3/mcm, a = 0.88655(8) nm, c = 0.65302(3) nm), Lu_5NiPb_3 (Hf_5CuSn_3 structure type, space group P6_3/mcm, a = 0.8775(1)nm, c = 0.65116(6)nm).