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  • 1
    Electronic Resource
    Electronic Resource
    Dependence of the diffraction angle on the surface microstructure of a steel sample (1991)
    Copenhagen : International Union of Crystallography (IUCr)
    Applied crystallography online 24 (1991), S. 928-930 
    Details
    ISSN: 1600-5767
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Geosciences , Physics
    Notes: While the deviations from linearity of ε−sin2ψ curves in the case of two welded hot-rolled C40 steel bars were being studied, this paper was prompted by the observation that, at ψ = 0°, the diffraction angle 2θ depends on φ, the inclination angle of the diffraction plane with respect to an arbitrarily chosen reference plane attached to the specimen. This result is unexpected and cannot be explained by bulk structural or microstructural factors. A surface effect is offered as a possible explanation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S0021889891004995
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Micro X-ray diffraction on capillary powder samples: a novel and effective technique for overcoming preferred orientation (2001)
    Copenhagen : International Union of Crystallography (IUCr)
    Applied crystallography online 34 (2001), S. 663-665 
    Details
    ISSN: 1600-5767
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Geosciences , Physics
    Notes: In past years, both experimental and analytical approaches have been developed for eliminating preferred orientation effects on powder X-ray diffraction patterns. The state of the art does not allow one to face the problem without difficult sample treatments, mechanical randomization, pole-figure study or pattern fitting based on the Rietveld approach. These methods are time consuming or need the knowledge of all the structural parameters, and, moreover, must be managed by specialized operators. Besides, none of the above techniques can be applied to powder samples of drugs loaded into polymeric carriers, the diffraction patterns of which present a structured amorphous halo from which the crystalline drug peaks rise up. In this paper, it is shown that micro X-ray diffraction on capillary powder samples, combined with a two-dimensional detector, is a promising solution to preferred orientation problems, since it provides easy and rapid preparation of randomly oriented powder samples, fast measurements (acquisition times of a few minutes) and correct powder diffraction patterns.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S0021889801012237
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Structure and properties of lanthanide catalysts: the crystal and molecular structure of SmBr3·4iPr(OH) (1991)
    Springer
    Structural chemistry 2 (1991), S. 595-600 
    Details
    ISSN: 1572-9001
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The crystal of the title compound is monoclinic (space group C2/c), with a = 22,067(17), b = 10.111 (10), c = 16.886(11) Å,β=142.95(5)°, and Z = 4. Its structure is based on the packing of SmBr3·4iPr(OH) (iPr = isopropyl) molecules. The metal atom is coordinated by three Br ions and by the oxygen atoms of the four iPr(OH) ligands. The coordination polyhedron is a distorted pentagonal bipyramid of C2 symmetry, with Sm and one of the Br atoms lying on the twofold axis of crystallographic symmetry. Polymerization experiments are reported showing that the activity of the catalytic system based on the title complex is much lower than that shown by systems based on similar Nd complexes. A possible rationalization of this fact is given in terms of the oxidation capacity of the rare-earth ions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00673443
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Derivation of structural models for two intercalated compounds of α-zirconium phosphate (1993)
    Springer
    Structural chemistry 4 (1993), S. 317-321 
    Details
    ISSN: 1572-9001
    Keywords: X-ray crystallography ; comparison method ; hydrogen bonding ; intercalation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Reasonable structural models are proposed for two intercalated compounds ofα-Zr(HPO4)2·H2O (α-ZrP), one with 2,2′-bipyridyl (A) and another one with 1,10-phenanthroline (B). The models are derived by considerations of the unit-cell geometry changes undergone byα-ZrP upon insertion of the organic molecules and on a set of general criteria of structural analysis, already developed by us and called the comparison method. If it is assumed that the water molecules in A and B keep the positions they have inα-ZrP, as fixed by their links to the phosphate-OH groups, the inserted molecules, while obeying the general conditions of optimum packing, establish interactions of the hydrogen-bonding type with the water molecules. This modeling gives for A and B a possible structural explanation to the maximum number of inserted molecules of the two species, as fixed by their stoichiometry.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00681205
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    Paper (German National Licenses)
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  • 5
    Electronic Resource
    Electronic Resource
    Diffraction and XPS studies of Cu complexes of intercalated compounds of α-zirconium phosphate. I: Derivation of structural models from powder diffraction data (1994)
    Springer
    Structural chemistry 5 (1994), S. 15-20 
    Details
    ISSN: 1572-9001
    Keywords: Structural modeling ; intercalated compounds ; powder diffraction ; α-zirconium phosphate derivates ; copper complexes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Reasonable structural models are proposed for the Cu complexes of two intercalated compounds of α-Zr(HPO4)2·H2O (α-ZrP): one with 1,10-phenanthroline (A) and the other with 2,2′-bipyridyl (B). The models are derived from considerations of the unit-cell geometry changes undergone by α-ZrP upon insertion of, first, the organic molecules and then copper, in accordance with a set of general criteria of structural analysis called the “comparison method.”
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02278691
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    Paper (German National Licenses)
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