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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    H. P. FritzRequires cookie*
 Title    The Stannides RE R hSn (RE = Ho -Yb) and ScTSn (T = Pd, Pt) -Structure Refinements and 119Sn Mössbauer Spectroscopy  
 Abstract    The stannides RERhSn (RE = Ho -Yb) and ScTSn (T = Pd, Pt) were prepared by reaction of the elements in sealed tantalum tubes in a high-frequency furnace, by arc-melting, or by a tin-flux technique in quartz tubes. The rhodium based stannides crystallize with the ZrNiAl type structure, space group P62m. The four structures were refined from single crystal X-ray data: a = 754.5(3), c = 377.1(1) pm, wR2 = 0.0357, 233 F 2 values for HoRhSn, a = 753.3(1), c = 372.16(8) pm, wR2 = 0.0721, 233 F 2 values for ErRhSn, a = 753.7(3), c = 369.0(2) pm, wR2 = 0.0671,233 F 2 values for TmRhSn, and a = 753.17(5), c = 366.53(4) pm, wR2 = 0.0566, 180 F 2 values for YbRhSn with 14 parameters for each refinement. ScPdSn and ScPtSn adopt the HfRhSn type, a superstructure of ZrNiAl, space group P62c: a = 747.5(1), c = 710.2(1) pm, for ScPdSn, and a = 738.37(9), c = 729.47(9) pm, wR2 = 0.0452,369 F 2 values, 18 variables for ScPtSn. Structural motifs in these stannides are transition metal centered trigonal prisms formed by the rare earth and tin atoms. While these prisms are regular in the rhodium based stannides, significant distortions occur in ScPdSn and ScPtSn. The formation of the superstructure can be ascribed to packing reasons. The shortest interatomic distances occur between the transition metal (T) and tin atoms. These atoms form three-dimensional [FSn] networks in which the rare earth atoms fill distorted hexagonal channels. The series RERhSn displays a somewhat unique behavior. The a lattice parameter is more or less independent of the rare earth element, while the c lattice parameter shows the expected lanthanoid contraction. ll9Sn Mössbauer spectroscopic data of the rhodium stannides show signals at isomer shifts varying from 1.77 to 1.82 mm/s subject to quadrupole splitting between 0.75 to 0.82 mm/s. 
  Reference    Z. Naturforsch. 56b, 589—597 (2001); received April 12 2001 
  Published    2001 
  Keywords    Stannides, Crystal Structure, Mössbauer Spectroscopy 
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 TEI-XML for    default:Reihe_B/56/ZNB-2001-56b-0589.pdf 
 Identifier    ZNB-2001-56b-0589 
 Volume    56 
3Author    Wolfgang Blase, Gerhard CordierRequires cookie*
 Abstract    NaGaSn, (trigonal; P3,12 (No. 151); a = 632.8(4), c = 617.0(3) pm, Z -1; d v = 5.33 g/cm 3) was grown from the melt. The crystal structure contains Ga and Sn atoms in a helical arrangement (six atoms per turn) along the c-axis direction. Interatomic bonding between neighbouring helices completes a distorted [2+2]-tetrahedral environment for every Ga/Sn position. The compound is classified in terms of the Zintl concept. 
  Reference    Z. Naturforsch. 43b, 1017—1019 (1988); eingegangen am 28. März 1988 
  Published    1988 
  Keywords    Gallides, Stannides, Crystal Structure, Zintl-Phases 
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 TEI-XML for    default:Reihe_B/43/ZNB-1988-43b-1017.pdf 
 Identifier    ZNB-1988-43b-1017 
 Volume    43