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  • Wiley-Blackwell  (3)
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  • Wiley-Blackwell  (3)
  • Wiley  (3)
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  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 588 (1990), S. 109-116 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: BaCu8P4 and BaCu8As4: Preparation, Structure Determination, and HRTEM InvestigationsBaCu8P4 and BaCu8As4 have been prepared by heating the mixture of the elements. Both compounds crystallize in a tetragonal body-centred lattice (S.G. 14/m; lattice constants: BaCu8P4: a = 10.192(2)Å, c = 3.878(1)Å; BaCu8As4: a = 10.455(2)Å, c = 3.969(1) Å). The structure is characterized by a threedimensional Cu—P(As) network with two channels of different size, which are running parallel to the c axis. In the channel of larger cross section the Ba atoms are located, in the other one are infinite chains of edge shared Cu tetrahedra.BaCu8P4 was the first ternary phosphide which has been investigated by transmission electron microscopy. High resolution micrographs were taken at different values of defocus. They were compared with pictures obtained by computer simulations. These calculations show, that the Ba positions in the lager channels give a light contrast while the Cu—P network occurs dark. Since the experimental pictures are in good agreement with the calculated ones, the calculations can serve as an interpretation of the experimental results.
    Notes: BaCu8P4 und BaCu8As4 wurden durch Erhitzen der Elemente dargestellt; beide Verbindungen kristallisieren tetragonal-innenzentriert (RG I4/m) mit den Gitterkonstanten: BaCu8P4: a = 10,192(2) Å, c = 3,878(1) Å; BaCu8As4: a = 10,455(2) Å, c = 3,969(1) Å. Die Struktur wird von einem dreidimensionalen Cu—P(As)-Raumnetz geprägt, in dem parallel zur c-Achse zwei unterschiedlich große Kanäle verlaufen. In jenen mit größerem Durchmesser befinden sich die Ba-Atome, während sich durch die Kanäle mit kleinerem Querschnitt unendliche Ketten kantenverknüpfter Cu-Tetraeder ziehen.BaCu8P4 wurde als erstes ternäres Phosphid im Elektronenmikroskop untersucht. In Hochauflösung wurden Durchstrahlungsaufnahmen mit verschiedenen Defokus-Werten angefertigt und mit den durch Computersimulation erhaltenen Bildern verglichen. Aus den Rechnungen geht hervor, daß die Ba-Lagen in den Kanälen als helle Kontraste abgebildet werden, während die Cu—P-Baugruppen dunkel erscheinen. Wie die gute Übereinstimmung zwischen Experiment und Rechnung zeigt, darf man die experimentell erhaltenen Aufnahmen in dieser Weise interpretieren.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 582 (1990), S. 224-224 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 581 (1990), S. 173-182 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Ternary BaAl4-Type Derivatives. Preparation and Crystal Structure of CaCu2As2, Ca2Cu6P5, and Ba2Cu3P4CaCu2As2, Ca2Cu6P5, and Ba2Cu3P4 (space groups and lattice constants see „Inhaltsübersicht“) have been prepared by heating the elements. Their structures are ternary BaAl4-type derivatives.CaCu2As2 (with a partial unoccupation of the Cu positions) crystallizes in a ThCr2Si2-type structure, whereas the structure of Ca2Cu6P5 is built up by stacking three unit cells of CaCu2P2 (ThCr2Si2-type) on top of each other and taking away two Ca—P-layers. The atomic arrangement of Ba2Cu3P4 can be interpreted as a new variant of the ThCr2Si2-type structure too with bands of edge shared CuP4-tetrahedra and characteristic P2-pairs.
    Notes: CaCu2As2 (I4/mmm, a = 412,9(1) pm, c = 1 025,1(1) pm, Z = 2) kristallisiert im ThCr2Si2-Typ, die Cu-Punktlage ist wie bei dem isotypen Phosphid unterbesetzt. Die Struktur von Ca2Cu6P5 (I4/mmm, a = 410,5(1) pm, c = 2 465,7(2) pm, Z = 2) besteht aus drei übereinander gestapelten Blöcken des ThCr2Si2-Typs, wobei allerdings zwei Ca—P-Lagen fehlen. Die Atomanordnung von Ba2Cu3P4 (Ibam, a = 934,7(2) pm, b = 1 241,5(2) pm, c = 618,8(1) pm, Z = 4) kann als neue Variante der ThCr2Si2-Struktur beschrieben werden, bei welcher Bänder von kantenverknüpften CuP4-Tetraedern sowie charakteristische P2-Hanteln strukturbestimmende Merkmale sind.
    Additional Material: 2 Ill.
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