Ce2PdIn8, Ce3PdIn11 and Ce5Pd2In19—members of homological series based on AuCu3- and PtHg2-type structural units

Crystal structures of three members of a unique homological series with the general formula CemPdnIn3m+2n based on the AuCu3 and PtHg2 structure types were studied by single-crystal X-ray diffraction. The compounds crystallize with space group P4/mmm (Z=1) and the lattice parameters: a=4.6900(9) Å, c=12.185(6) Å for Ce2PdIn8, a=4.6846(8) Å, c=16.846(8) Å for Ce3PdIn11, and a=4.70120(10) Å, c=29.1359(4) Å for Ce5Pd2In19. The crystal structures of Ce3PdIn11 and Ce5Pd2In19 represent new types. The three structures constitute of [CeIn3] cuboctahedra layers and [PdIn2] rectangular polyhedra layers, alternating along the tetragonal c-axis in accordance with the m:n proportion. The magnetic and electrical transport properties of the novel compounds Ce3PdIn11 and Ce5Pd2In19 were investigated down to 1.72 K. Both indides are Curie–Weiss paramagnets due to the presence of fairly well localized 4f electrons of trivalent cerium ions. The electrical resistivity of both materials is dominated over an extended temperature range by strong spin–flip Kondo interactions with the characteristic temperature scale of 20–30 K.