Syntheses and Structures of RE4Pt10In21 (RE = La–Nd)

Abstract

AbstractThe isotypic indides RE4Pt10In21 (RE = La, Ce, Pr, Nd) were prepared by melting mixtures of the elements in an arc‐furnace under an argon atmosphere. Single crystals were synthesized in tantalum ampoules using special temperature modes. The four samples were studied by powder and single crystal X‐ray diffraction: Ho4Ni10Ga21 type, C2/m, a = 2305.8(2), b = 451.27(4), c = 1944.9(2) pm, β = 133.18(7)°, wR2 = 0.045, 2817 F2 values, 107 variables for La4Pt10In21, a = 2301.0(2), b = 448.76(4), c = 1941.6(2) pm, β = 133.050(8)°, wR2 = 0.056, 3099 F2 values, 107 variables for Ce4Pt10In21, a = 2297.4(2), b = 447.4(4), c = 1939.7(2) pm, β = 132.95(1)°, wR2 = 0.059, 3107 F2 values, 107 variables for Pr4Pt10In21, and a = 2294.7(4), b = 446.1(1), c = 1938.7(3) pm, β = 132.883(9)°, wR2 = 0.067, 2775 F2 values, 107 variables for Nd4Pt10In21. The 8j In2 positions of all structures have been refined with a split model. The In1 sites of the lanthanum and the cerium compound show small defects, leading to the refined composition La4Pt10In20.966(6) and Ce4Pt10In20.909(6) for the investigated crystals. The same position shows Pt/In mixing in the praseodymium and neodymium compound leading to the refined compositions Pr4Pt10.084(9)In20.916(9) and Nd4Pt10.050(9)In20.950(9). All platinum atoms have a tricapped trigonal prismatic coordination by rare‐earth metal and indium atoms. The shortest interatomic distances occur for Pt–In followed by In–In. Together, the platinum and indium atoms build up three‐dimensional [Pt10In21] networks in which the rare earth atoms fill distorted pentagonal tubes. The crystal chemistry of RE4Pt10In21 is discussed and compared with the RE4Pd10In21 indides and isotypic gallides.