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1998 (1)
1993 (2)
1Author    V. Massarotti, D. Capsoni, M. Bini, C. B. Azzoni, M. C. Mozzati, A. PaleariRequires cookie*
 Title    Structural and Magnetic Characterization of Mixed Oxides: A Study of Li-Ni-O and Li-Mn-O Systems  
 Abstract    The present paper details the way to determine the cation distribution in mixed oxides with transition ions from the diffraction and magnetic susceptibility data. This approach allows one to determine phase abundances and phase compositions by two combined procedures. By X-ray diffraction Rietveld pro-file refinement and magnetic susceptibility data analysis it is possible to estimate the ratio and the oc-cupancy factor of paramagnetic ions in different oxidation states. A brief discussion of practical cases is reported. In the Li-Ni-0 system the lithium cationic fraction of the ordered phase Li 2r Ni2_2 X 0 2 in-creases monotonically with the total lithium fraction x, for 0.31 < x, < 0.46. In the Li-Mn-0 system for 0.36 < JC, < 0.53 the Li 2 Mn0 3 fraction has been determined, and for the coexistent Li [Li-y Mn 2 _ > ,] 0 4 spi-nel phase the dependence of y on x t has been evaluated. 
  Reference    Z. Naturforsch. 53a, 150—156 (1998); received January 30 1998 
  Published    1998 
  Keywords    X-ray Powder Diffraction, Magnetic Susceptibility, Lithium Nickel Oxides, Lithium Man-ganese Oxides, Lithium Manganese Spinel 
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 TEI-XML for    default:Reihe_A/53/ZNA-1998-53a-0150.pdf 
 Identifier    ZNA-1998-53a-0150 
 Volume    53 
2Author    Ryosei Uno, Haruo Ozawa, Jun Ishigaki, Ken YukinoRequires cookie*
 Title    Electron Distribution in Some Zincblende-Type Crystals  
 Abstract    The elctron density distribution in crystalline ZnSe and ZnTe has been measured by X-ray diffraction on powder samples and is compared with the results for other zincblende-type crystals. It is shown that the data for these two compounds corroborate the linear dependence on the bond charge that has been found earlier for the effective atomic charge from infrared reflection measure-ments, the optical dielectric constant and the ionicity estimated from pseudopotential band theory. 
  Reference    Z. Naturforsch. 48a, 38—40 (1993); received January 10 1992 
  Published    1993 
  Keywords    Zincblende-type crystals, Bond charge, Ionicity, X-ray powder diffraction, Electron density distribution 
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 TEI-XML for    default:Reihe_A/48/ZNA-1993-48a-0038.pdf 
 Identifier    ZNA-1993-48a-0038 
 Volume    48 
3Author    Masaki Takata, Yoshiki Kubota, Makoto SakataRequires cookie*
 Title    The Electron Density Distribution in Be Metal Obtained from Synchrotron-Radiation Powder Data by the Maximum-Entropy Method  
 Abstract    The nature of the bonding in Be metal was studied by investigating the MEM map, which is the electron density distribution obtained by the Maximum-Entropy Method. In order to avoid extinc-tion effects, 19 Bragg reflections were measured by a new powder-diffraction experiment that utilizes Synchrotron Radiation as an incident X-ray and an Imaging Plate as detector. The experiment was carried out at the Photon Factory BL6A2. In spite of the limited number of reflections used in the MEM analysis, the electron density distribution of Be was obtained accurately and reliably. The structure factors for unmeasured reflections were calculated and compared with the values observed by Larsen and Hansen [Acta Cryst. B40, 169 (1984)]. The agreement is very good. Furthermore, the MEM map revealed that Be metal forms an electronic layer in the shape of a honeycomb that is parallel to the basal plane. 
  Reference    Z. Naturforsch. 48a, 75—80 (1993); received December 28 1991 
  Published    1993 
  Keywords    Maximum entropy method, Be metal, Electron density distribution, X-ray powder diffraction, HCP structure 
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 TEI-XML for    default:Reihe_A/48/ZNA-1993-48a-0075.pdf 
 Identifier    ZNA-1993-48a-0075 
 Volume    48