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The title new compounds with chemical formula RNixBi2 were synthesized by arc melting method followed by annealing. The crystal structures refined by using Rietveld method and X-ray powder diffraction data are isotypic to CaMnBi2 structure type, space group P4/nmm with a = 0.448350(4), c = 0.930026(2) nm, V = 0.186952(7) nm3 for YNi0.82Bi2, a = 0.448882(5), c = 0.93658(2) nm, V = 0.188715(8) nm3 for GdNi0.86Bi2, a = 0.448486(3), c = 0.93062(2) nm, V = 0.187185(6) nm3 for TbNi0.78Bi2 and a = 0.447493(4) nm, c = 0.925852(1) nm, V = 0.185402(6) nm3 for DyNi0.77Bi2, showing lanthanide contraction. The structure is characterized by layers of edge-sharing NiBi4 tetrahedron and covalently bonded Bi square net separated by rare earth atoms.
The crystal compounds refined by using Rietveld method and X-ray powder diffraction data are isotypic to CaMnBi2 structure type, space group P4 / nmm with a = 0.448350 ( 4 = 0.930026 (2) nm, V = 0.186952 (7) nm3 for YNi0.82Bi2, a = 0.448882 (5), c = 0.93658 (2) nm, V = 0.188715 (8) nm3 for GdNi0.86Bi2, a = 0.448486 (3), c = 0.93062 (2) nm, V = 0.187185 (6) nm3 for TbNi0.78Bi2 and a = 0.447493 (4) nm, c = 0.925852 (1) nm, V = 0.185402 (6) nm3 for DyNi0.77Bi2, showing lanthanide contraction. The structure is characterized by layers of edge-sharing NiBi4 tetrahedron and covalently bonded Bi square net separated by rare earth atoms.