issue contents

ISSN: 2053-2733

November 2013 issue

Highlighted illustration

Cover illustration: Experimental charge-density studies of heavy-element, inorganic solids are highly challenging. The experimental static deformation density in a plane for such a compound, CoSb3, is shown. The positive features in between Co and Sb indicate a covalent character of the Co-Sb bond [Schmøkel et al. (2013). Acta Cryst. A69, 570-582].


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The scope of Acta Crystallographica Section A is outlined and new section for high-impact articles, Advances, is announced.

research papers

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Examples are given of nets describing the topology of real crystal structures in which groups of vertices collide in barycentric coordinates and in high-symmetry embeddings.

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Two systems are homometric if they are indistinguishable by diffraction. This article mainly discusses the issue of diffuse scattering homometry and its relation to high-order correlation functions. The study of the Rudin–Shapiro sequence, homometric to random sequences, allows one to manipulate independently two-point and four-point correlation functions, and to show their effect on the statistics of speckle patterns.

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Predictions for residual values based on the experimental data and on knowledge of the number of model parameters used to fit the experimental data are presented. Applications to crystallographic residual values are discussed.

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A new direct phasing method is introduced that exploits small shifts in the positions of Bragg peaks in a nanocrystal diffraction pattern.

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Experimental electron-density studies of inorganic, extended solids containing heavy elements are highly challenging. Such a study on a particularly problematic case, CoSb3, is presented and discussed.

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The structure of particular hollow-cage fullerenes is described in exact coordinates, and their existence explained from a symmetry-breaking mechanism starting from the perfect icosahedral symmetry of C60. The mechanism is extended to also describe the possible construction of larger nanostructures such as carbon nanotubes, as well as sets of stereoisomers of the C60 molecule.

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A Clifford spinor construction shows how the Platonic solids induce their four-dimensional counterparts and determine their symmetries.

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Spin line groups, describing magnetic symmetries of quasi-one-dimensional systems, are studied and derived for the first family line groups. Corresponding spin arrangements are discussed and illustrated by several examples.

book reviews

international union of crystallography

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