Ternary Indides RE4Pd10In21 (RE = La, Ce, Pr, Nd, Sm) — Synthesis, Structure, and Physical Properties

Abstract

AbstractThe ternary indium compounds RE4Pd10In21 (RE = La, Ce, Pr, Nd, Sm) were synthesized from the elements in glassy carbon crucibles in a high‐frequency furnace. Single crystals of Sm4Pd10In21 were obtained from an indium flux. An arc‐melted precursor alloy of the starting composition ∼SmPd3In6 was annealed with a slight excess of indium at 1200 K followed by slow cooling (5 K/h) to 870 K. All compounds were investigated by X‐ray powder diffraction and the structures were refined from single crystal diffractometer data. The RE4Pd10In21 indides are isotypic with Ho4Ni10Ga21, space group C2/m: a = 2314.3(2), b = 454.70(7), c = 1940.7(2) pm, β = 133.43(2)°, wR2 = 0.0681, 1678 F2 values for La4Pd10In21, a = 2308.2(1), b = 452.52(4), c = 1944.80(9) pm, β = 133.40(1)°, wR2 = 0.0659, 1684 F2 values for Ce4Pd10In21, a = 2303.8(2), b = 450.78(4), c = 1940.6(1) pm, β = 133.39(1)°, wR2 = 0.0513, 1648 F2 values for Pr4Pd10In21, a = 2300.2(2), b = 449.75(6), c = 1937.8(2) pm, β = 133.32(1)°, wR2 = 0.1086, 1506 F2 values for Nd4Pd10In21, and a = 2295.6(2), b = 447.07(4), c = 1935.7(1) pm, β = 133.16(1)°, wR2 = 0.2291, 2350 F2 values for Sm4Pd10In21, with 108 variables per refinement. All palladium atoms have a trigonal prismatic coordination. The strongest bonding interactions occur for the Pd—In and In—In contacts. The structures are composed of covalently bonded three‐dimensional [Pd10In21] networks in which the rare earth metal atoms fill distorted pentagonal channels. The crystal chemistry and chemical bonding in these indides is briefly discussed. Magnetic susceptibility measurements show diamagnetism for La4Pd10In21 and Curie‐Weiss paramagnetism for Ce4Pd10In21, Pr4Pd10In21, and Nd4Pd10In21. The neodymium compound orders antiferromagnetically at TN = 4.5(2) K and undergoes a metamagnetic transition at a critical field of 1.5(2) T. All the RE4Pd10In21 indides studied are metallic conductors.