issue contents

ISSN: 2053-2733

January 2010 issue

Highlighted illustration

Cover illustration: A collage of related patterns that are formed via tilings of the hyperbolic plane. Two-dimensional `universal tilings' (e.g. UQC473) of hyperbolic space can be wrapped onto a three-periodic minimal surface (e.g. the  gyroid), forming a curvilinear `Epinet tiling' (EGC473) whose edges relax to give a `Systre net', sqc14527. This approach to net enumeration is described in Ramsden et al. [Acta Cryst. (2009), A65, 81-108]. Further examples are collected at

feature articles

Acta Cryst. (2010). A66, 1-4
doi: 10.1107/S0108767309041853
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This article describes the circumstances of the establishment of the European Crystallographic Committee, now the European Crystallographic Association, a regional associate of the IUCr, and of the European Crystallographic Meetings.

research papers

Acta Cryst. (2010). A66, 5-9
doi: 10.1107/S0108767309044183
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A new method of generating quasicrystalline patterns with 12-fold symmetry from tilings by squares and equilateral triangles is described.

Acta Cryst. (2010). A66, 10-16
doi: 10.1107/S0108767309039750
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It is found that the intensities of bright spots in a spherical aberration (Cs)-uncorrected high-angle annular dark-field (HAADF) scanning transmission electron microscope (STEM) image of [011]-oriented Co3O4 change with sample thickness. From an analysis based on the Bloch-wave theorem, it is found that an insufficient semiangle of the incident convergent beam leads to intensities that do not depend on the average atomic number in the atomic columns.

Acta Cryst. (2010). A66, 17-21
doi: 10.1107/S010876730904522X
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The phase shift of the transmitted neutron beam in Laue geometry is investigated by neutron interferometry.

Acta Cryst. (2010). A66, 22-31
doi: 10.1107/S0108767309045206
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The structure factors for amorphous silicon and vitreous silica are determined in the long-wavelength limit from large computer models and compared with available experiments.

Acta Cryst. (2010). A66, 32-37
doi: 10.1107/S0108767309041749
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The azimuthally projected electron density of an isolated molecule of high degree of rotational symmetry about an alignment axis may be reconstructed by an iterative phasing algorithm applied to the diffuse diffraction pattern from an ensemble and beam incidence normal to the molecular alignment axis.

Acta Cryst. (2010). A66, 38-49
doi: 10.1107/S0108767309046777
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Experimental crystal structures that are amenable for inclusion in global phase diagrams as previously developed are identified.

Acta Cryst. (2010). A66, 50-63
doi: 10.1107/S0108767309047643
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A small number of parameters describe a rich variety of phases in tetrahedral molecular crystals found in the Cambridge Structural Database.

Acta Cryst. (2010). A66, 64-77
doi: 10.1107/S0108767309039890
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A method is described for the calculation of X-ray or neutron diffraction patterns of conventional crystalline powders based on the Debye scattering equation. Full background and reflection profiles are generated, whereby the effects of crystallite size and static and thermal disorder are also taken into account.

Acta Cryst. (2010). A66, 78-92
doi: 10.1107/S0108767309038744
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The X-ray constrained unrestricted Hartree–Fock approach at the Douglas–Kroll–Hess and the nonrelativistic level of theory is presented. The relativistic and X-ray constraint effects in structural data, electron and spin density are reported.

Acta Cryst. (2010). A66, 93-97
doi: 10.1107/S0108767309044791
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Scattering at small angles for cylindrical tubules has been theoretically studied. From the intensities at second angles of scattering, physical and chemical parameters of the tubules can be determined.

international union of crystallography

Acta Cryst. (2010). A66, 127
doi: 10.1107/S0108767309050636

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