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2000 (1)
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1Author    MarkusF. Zumdick, Rainer PöttgenRequires cookie*
 Title    Condensed [Ru4Sn6] Units in the Stannides LnRu4Sn6 (Ln = La, Pr, Nd, Sm, Gd) -Synthesis, Structure, and Chemical Bonding  
 Abstract    The stannides LnRu4Sn6 (Ln = La, Pr, Nd, Sm, Gd) were prepared by reaction of the elements in an arc-melting furnace and subsequent annealing at 1120 K. The praseodymium, the neodymium, and the samarium stannide were obtained for the first time. The LnRu4Sn6 stannides were investigated by X-ray diffraction both on powders and single crystals. They adopt the YRu4Sn6 type structure which was refined from single crystal X-ray data for the samarium and the gadolinium compound: /42m, a = 686.1 (1), c = 977.7(2) pm, wR2 = 0.0649, 483 F2 values for SmRu4Sn6, and a = 685.2(1), c = 977.6(3) pm, wR2 = 0.0629, 554 F2 values for GdRu4Sn6 with 19 variables for each refinement. The striking structural motif of these stannides are distorted RuSnö octahedra with Ru-Sn distances ranging from 257 to 278 pm. Four of such octahedra are condensed via common edges and faces forming [Ru4Snö] units which are packed in a tetragonal body-centered arrangement. The rare-earth atoms fill the voids between the [Ru4Sn6] units. Based on an extended Hückel calculation, strong bonding interactions were found for the Ru-Sn and the various Sn-Sn contacts. 
  Reference    Z. Naturforsch. 54b, 863—869 (1999); received March 29 1999 
  Published    1999 
  Keywords    Stannides, Crystal Structure, Chemical Bonding 
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 TEI-XML for    default:Reihe_B/54/ZNB-1999-54b-0863.pdf 
 Identifier    ZNB-1999-54b-0863 
 Volume    54 
2Author    Rolf-Dieter Hoffmanna, Rainer Pöttgen3, '. I. Vasyl, YaroslavM. Zarembab, KalychakbRequires cookie*
 Title    New Indides EuAuIn2, EuPdIn4, G dR hIn2, Y bR hIn4, and YbPdIn4  
 Abstract    New intermetallic indium compounds EuAuIn2, EuPdIn4, GdRhIn2, YbRhln*, and YbPdlru were obtained by reaction of the elements. GdRhIn2 was synthesized in an arc-melting furnace, while EuAuIn2, EuPdln*, YbRhIn4, and YbPdIn4 were prepared in sealed tantalum tubes in a high-frequency furnace. The five compounds were investigated by X-ray diffraction both on powders and single crystals. EuAuIn2 and GdRhIn2 adopt the MgCuA^ type structure 
  Reference    Z. Naturforsch. 55b, 834—840 (2000); received July 10 2000 
  Published    2000 
  Keywords    Intermetallic Compounds, Indium, Chemical Bonding 
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 TEI-XML for    default:Reihe_B/55/ZNB-2000-55b-0834.pdf 
 Identifier    ZNB-2000-55b-0834 
 Volume    55 
3Author    Z. NaturforschRequires cookie*
 Title    SrRhIn2, SrPdIn2, Srlrln2, and SrPtIn2 -New Intermetallic Compounds with a Filled Variant of the Caln2 Structure  
 Abstract    SrR hlm , SrPdIn2, Srlrln2, and SrPtIn2 have been synthesized by reaction of mixtures of the elements in glassy carbon crucibles in a high-frequency furnace. The new compounds were investigated by X-ray diffraction on powders as well as single crystals; a = 437.3(2), b = 1091.9(5), c = 798.0(2) pm for SrRhln^, a = 453.54(7), b = 1079.8(2), c = 790.4(1) pm for SrPdIn2, a = 434.83(8),b= 1102.6(2) ,c = 798.6(2) pm for Srlrln2, a = 447.5(1) , b = 1091.0(3), c = 787.6(1) pm for SrPtIn2. They adopt the MgCuAl2 structure, a ternary ordered version of Re^B. Chemical bonding analysis leads to the description of a filled S rln2 structure in which the In-in-bonding is modified by the insertion of transition metal atoms into the planar strontium layers, thus favoring strong indium-transition metal 
  Reference    (Z. Naturforsch. 54b, 38—44 [1999]; received August 28 1998) 
  Published    1999 
  Keywords    Intermetallic Compounds, Crystal Structure, Chemical Bonding 
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 TEI-XML for    default:Reihe_B/54/ZNB-1999-54b-0038.pdf 
 Identifier    ZNB-1999-54b-0038 
 Volume    54 
4Author    MarkusF. Zum, R. Olf-D, Hoffm Ieter, Rainer Ann, PöttgenRequires cookie*
 Title    The Intermetallic Zirconium Compounds ZrNiAl, ZrRhSn, and ZrPtGa -Structural Distortions and Metal-Metal Bonding in Fe2P Related Compounds  
 Abstract    ZrNiAl, ZrPtGa, and ZrRhSn have been prepared by reacting the elements in an arc-melting furnace and subsequent annealing at 970 K. These compounds have previously been investigated only by use of X-ray powder data for ZrPtGa and ZrRhSn and single crystal film data for ZrNiAl. Precise single crystal diffractometer data are reported in the present paper. The structure of ZrNiAl is confirmed. It adopts a substitution variant of the FeiP type: P62m, a = 691.5(2), c = 346.6(1) pm, Z = 3, wR2 = 0.0538, 320 F2 values, 14 parameters. The structure refinement reveals a large displacement parameter U 33 for one nickel position, indicative of a slight nickel dislocation. Weak superstructure reflections could be found on Guinier powder patterns for ZrPtGa and ZrRhSn. These compounds crystallize with the HfRhSn type structure (Z = 6 , space group P62c), a superstructure of the Fe2P type: a = 714.5(1), c = 706.3(2) pm, w/?2 = 0.0651, 594 F2 values, 18 parameters for ZrPtGa and a = 734.2(2), c = 721.8(2) pm, wR2 = 0.0349, 355 F2 values, 18 parameters for ZrRhSn. Structural motifs of these compounds are transition metal centered trigonal prisms formed by the zirconium, aluminium, gallium, and tin atoms. While these trigonal prisms are regular in ZrNiAl, significant distortions occur in the structures of ZrPtGa and ZrRhSn. Due to the distortions of the trigonal prisms in the superstructures, some platinum and rhodium atoms are dislocated from the subcell mirror planes towards Pt-Pt and Rh-Rh pairs with distances o f 310 and 313 pm, respectively. The formation of the superstructure is most likely due to packing reasons. Chemical bonding in ZrRhSn was investigated on the basis of an extended Hückel calculation. 
  Reference    (Z. Naturforsch. 54b, 45—53 [1999]; received August 20 1998) 
  Published    1999 
  Keywords    Intermetallic Compounds, Crystal Structure, Superstructure, Chemical Bonding 
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 TEI-XML for    default:Reihe_B/54/ZNB-1999-54b-0045.pdf 
 Identifier    ZNB-1999-54b-0045 
 Volume    54 
5Author    Rolf-Dieter Hoffmann3, Dirk Kußmanna, Ute Ch, Rainer Rodewald3, Pöttgen3, Carsten Rosenhahnb, BerndD. MoselbRequires cookie*
 Title    New Stannides CaTSn2 (T = Rh, Pd, Ir) and Ca2Pt3 Sn5 -Synthesis, Structure and Chemical Bonding  
 Abstract    New stannides CaTSm (T = Rh, Pd, Ir) and Ca2P hSn5 were prepared as single phase materials by a reaction o f the elements in glassy carbon crucibles under flowing purified argon. The four compounds were investigated by X-ray diffraction both on powders and single crystals and their structures were refined from single crystal data. The stannides CaTSn2 (T = Rh, Pd, Ir) adopt 
  Reference    Z. Naturforsch. 54b, 709 (1999); received February 25 1999 
  Published    1999 
  Keywords    Intermetallic Calcium Compounds, Crystal Structure, Mössbauer Spectroscopy, Chemical Bonding 
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 TEI-XML for    default:Reihe_B/54/ZNB-1999-54b-0709.pdf 
 Identifier    ZNB-1999-54b-0709 
 Volume    54 
6Author    Wolfgang Jeitschko, Jörg Wallinda, MartinV. Dewalsky, Ulrich WortmannRequires cookie*
 Title    Preparation, Properties, and Structure of the Polyphosphides VM4P16, NbNi4P16, and WNi4P16  
 Abstract    The title compounds were prepared by reacting powders of the binary transition metal alloys with phosphorus in a tin melt. They crystallize with a monoclinic structure of space group C 2/c, which was determined from single-crystal X-ray data; VNi4P16: a = 1956.0(3), b = 565.9(1), c = 1106.6(2) pm, ß = 100.99(1)°, R -0.020 for 1904 structure factors and 97 variable parameters; NbNi4P16: a = 1973.0(3), b = 571.2(3), c = 1117.2(2) pm, ß = 100.74(1)°, R = 0.023 for 2431 F-values and 97 variables; WNi4P16: a = 1964.2(3), b = 568.3(2), c = 1109.3(2) pm,/? = 101.04(2)°, R = 0.031 for 371 F-values and 43 variables. The T atoms (T = V, Nb, W) have eight P neighbors, which form a slightly distorted square antiprism, and the Ni atoms have appro­ ximately octahedral P coordination. The P atoms form novel P8 units, which consist of 6 -mem-bered rings with a P2 side chain. Chemical bonding is discussed on the basis of classical two-electron bonds. A comparison of the interatomic distances suggests that the Fermi level cuts through a band formed by antibonding nickel-phosphorus states. A band structure is propos­ ed, which also rationalizes the metallic conductivity and the Pauli paramagnetism of the com­ pounds. 
  Reference    Z. Naturforsch. 48b, 1774—1780 (1993); received July 291993 
  Published    1993 
  Keywords    Crystal Structure, Magnetic Properties, Electrical Conductivity, Chemical Bonding, Transition Metal Polyphosphides 
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 TEI-XML for    default:Reihe_B/48/ZNB-1993-48b-1774.pdf 
 Identifier    ZNB-1993-48b-1774 
 Volume    48