Go toArchive
Browse byFacets
Bookbag ( 0 )
'Chemical bonding' in keywords Facet   Publication Year 1999  [X]
Results  4 Items
Sorted by   
Section
Publication Year
1999[X]
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 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_B/54/ZNB-1999-54b-0863.pdf 
 Identifier    ZNB-1999-54b-0863 
 Volume    54 
2Author    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 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_B/54/ZNB-1999-54b-0038.pdf 
 Identifier    ZNB-1999-54b-0038 
 Volume    54 
3Author    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 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_B/54/ZNB-1999-54b-0045.pdf 
 Identifier    ZNB-1999-54b-0045 
 Volume    54 
4Author    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 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_B/54/ZNB-1999-54b-0709.pdf 
 Identifier    ZNB-1999-54b-0709 
 Volume    54