Trinath Mishra

Structure and properties of EuTSb (T = Cu, Pd, Ag, Pt, Au) and YbIrSb

Abstract The equiatomic antimonides EuTSb (T = Cu, Pd, Ag, Pt, Au) and YbIrSb were synthesized from the elements in sealed tantalum tubes in an induction furnace. The samples were investigated by powder X-ray diffraction and the structures were refined on the basis of single crystal X-ray diffractometer data: ZrBeSi type, P63/mmc, a = 450.7(5), c = 853.2(7) pm, wR2 = 0.032, 273 F2 values, 8 variables for EuCuSb, a = 474.9(1), c = 829.4(3) pm, wR2 = 0.028, 166 F2 values, 8 variables for EuAgSb, a = 467.1(2), c = 848.8(3) pm, wR2 = 0.042, 162 F2 valäues, 8 variables for EuAuSb, and TiNiSi type, space group Pnma, a = 762.5(3), b = 469.1(1), c = 792.1(1) pm, wR2 = 0.046, 670 F2 values, 20 variables for EuPdSb, and a = 700.7(1), b = 444.68(8), c = 781.3(1) pm, wR2 = 0.075, 592 F2 values, 20 variables for YbIrSb. The structures are ordered superstructure variants of the aristotype AlB2 with planar T3Sb3 hexagons in EuTSb (T = Cu, Ag, Au) and puckered T3Sb3 hexagons in EuTSb (T = Pd, Pt) and YbIrSb. TiNiSi type EuPtSb was characterized via powder data: a = 759.8(3), b = 465.4(3), c = 791.4(3) pm. Temperature dependent magnetic susceptibility measurements indicate antiferromagnetic ordering for all compounds. The samples were additionally characterized by 121Sb and 151Eu Mössbauer spectra.

Structure Refinement and Magnetic Properties of Ce2RuAl3 and a Group-Subgroup Scheme for Ce5Ru3Al2

The hexagonal Laves phase Ce2RuAl3 (≡ CeRu0.5Al1.5) was synthesized by high-frequencemelting of the elements in a sealed tantalum tube and subsequent annealing. The structure was refined from single-crystal X-ray diffraction data: MgZn2 type, P63/mmc, Z = 2, a = 565.38(9), c = 888.3(1) pm, wR2 = 0.0231, 193 F2 values and 13 parameters. The 2a (0.824 Ru + 0.176 Al) and 6h (0.956 Al + 0.044 Ru) Wyckoff positions show mixed occupancies leading to the composition CeRu0.48Al1.52 for the investigated crystal. The aluminum atoms build up Kagomé networks at z = 1/4 and z = 3/4 which are connected to a three-dimensional network by the ruthenium atoms. The cerium atoms fill cavities of coordination number 16 (3 Ru + 9 Al + 4 Ce) within the [RuAl3] network. The Ce2RuAl3 sample orders ferromagnetically at TC = 8.0(1) K. The cerium-rich aluminide Ce5Ru3Al2 shows unusually short Ce-Ru distances of 253 and 260 pm for the Ce1 position as a result of intermediate cerium valence. The structural distortions are discussed on the basis of a group-subgroup scheme for Pr5Ru3Al2 (space group I213) and the superstructure variant Ce5Ru3Al2 (space group R3). Graphical Abstract Structure Refinement and Magnetic Properties of Ce2RuAl3 and a Group-Subgroup Scheme for Ce5Ru3Al2 Keywords Cerium, Intermetallics, Crystal Structure, Magnetic Properties

Ternary Stannides RE3Ru4Sn13 (RE = La, Ce, Pr, Nd) – Structure, Magnetic Properties, and 119Sn Mössbauer Spectroscopy

The ternary stannides RE3Ru4Sn13 (RE = La, Ce, Pr, Nd) were obtained by arc-melting of the elements. The polycrystalline samples were characterized by powder X-ray diffraction. The structures of three compounds were refined from single-crystal diffractometer data: Yb3Rh4Sn13 type, Pm3̄n, a = 977.74(3) pm, wR2 = 0.0379, 280 F2 values for La3Ru4Sn13, a = 971.34(9) pm, wR2 = 0.0333, 274 F2 values for Ce3Ru4Sn13, a = 970.68(8) pm, wR2 = 0.0262, 272 F2 values for Nd3Ru4Sn13 with 13 variables per refinement. The structures consist of three-dimensional networks of condensed RuSn6/2 trigonal prisms with the RE (CN 16) and Sn2 (CN 12) atoms in two different types of cavities of the networks. The two crystallographically independent tin sites have been resolved by 119Sn Mössbauer spectroscopy. Temperature-dependent magnetic susceptibility measurements of Ce3Ru4Sn13 gave a reduced magnetic moment of 2.32 μB per Ce atom, indicating intermediate cerium valence. No magnetic ordering was evident down to 3 K. Graphical Abstract Ternary Stannides RE3Ru4Sn13 (RE = La, Ce, Pr, Nd) – Structure, Magnetic Properties, and 119Sn Mössbauer Spectroscopy

Intermetallic REPtZn Compounds with TiNiSi-type Structure

The equiatomic rare earth compounds REPtZn (RE = Y, Pr, Nd, Gd-Tm) were synthesized from the elements in sealed tantalum tubes by high-frequency melting at 1500 K followed by annealing at 1120 K and quenching. The samples were characterized by powder X-ray diffraction. The structures of four crystals were refined from single-crystal diffractometer data: TiNiSi type, Pnma, a = 707.1(1), b = 430.0(1), c = 812.4(1) pm, wR2 = 0.066, 602 F2, 21 variables for PrPt1.056Zn0.944; a = 695.2(1), b = 419.9(1), c = 804.8(1) pm, wR2 = 0.041, 522 F2, 21 variables for GdPt0.941Zn1.059; a = 688.2(1), b = 408.1(1), c = 812.5(1) pm, wR2 = 0.041, 497 F2, 22 variables for HoPt1.055Zn0.945; a = 686.9(1), b = 407.8(1), c = 810.4(1) pm, wR2 = 0.061, 779 F2, 20 variables for ErPtZn. The single-crystal data indicate small homogeneity ranges REPt1±xZn1±x. The platinum and zinc atoms build up three-dimensional [PtZn] networks (265 - 269 pm Pt-Zn in ErPtZn) in which the erbium atoms fill cages with coordination number 16 (6 Pt + 6 Zn + 4 Er). Bonding of the erbium atoms to the [PtZn] network proceeds via shorter RE-Pt distances, i. e. 288 - 293 pm in ErPtZn. Graphical Abstract Intermetallic REPtZn Compounds with TiNiSi-type Structure