Ternary indides RE 3 T 2In4 (RE=Dy–Tm; T=Pd, Ir)

Abstract

Abstract The ternary rare earth transition metal-indides RE 3 T 2In4 (RE=Dy–Tm; T=Pd, Ir) were obtained from high-temperature reactions in sealed niobium ampoules. These indides adopt a hexagonal structure of the Lu3Co1.87In4 type (space group P6̅), a ternary ordered superstructure of the aristotype Fe2P. The structures of three different compounds were refined from single-crystal X-ray diffractometer data: a=768.20(6), c=381.97(3) pm, 1441 F 2 values, 24 parameters, wR2=0.0338 (Ho3Pd1.90In4); a=774.98(3), c=378.51(2) pm, 577 F 2 values, 23 parameters, wR2=0.0742 (Ho3Ir1.69In4.31) and a=780.3(1), c=369.4(1) pm, 573 F 2 values, 22 parameters, wR2=0.0403 (Tm3Ir1.51In4.49). Refinements of the occupancies revealed homogeneity ranges in case of the iridium-based crystals resulting from Ir/In mixing. The refined composition of the palladium compound was Ho3Pd1.90In4 resulting from defects on the Wyckoff position 1d, which was already reported for the prototype Lu3Co1.87In4. The geometrical motifs of the RE 3 T 2In4 structures are three different types of tricapped trigonal prisms around the transition metal and indium atoms which are condensed via common edges and triangular faces. Temperature dependent magnetic susceptibility measurements of Dy3Ir2In4 and Tm3Ir2In4 showed Curie-Weiss behavior and the experimental magnetic moments of 10.59(2) μB (Dy3Ir2In4) and 7.40(2) μB (Tm3Ir2In4) confirming stable trivalent RE 3+ states. Dy3Ir2In4 and Tm3Ir2In4 order antiferromagnetically with Néel temperatures of T N=13.6(5) and 5.4(5) K, respectively.