issue contents

Journal logoSTRUCTURAL SCIENCE
CRYSTAL ENGINEERING
MATERIALS
ISSN: 2052-5206

December 2009 issue

Highlighted illustration

Cover illustration: Though cyclohexanol is a simple compound it has a rich phase diversity at low temperature. It forms a disordered glassy phase on cooling, but this can be transformed into ordered phases (II), (III) and the metastable (III'), which all have different hydrogen-bonding motifs.  The series of transitions is attributable to the conformational flexibility of the hydroxyl group [Ibberson et  al. (2008). Acta Cryst. B64, 573-582].

research papers


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This paper describes a novel method for the room-temperature growth of single crystals of phase-III KNO3 and refines its structure at both room temperature and 123 K.

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The magnetic structure of the synthetic cobalt olivine, Co2SiO4, is determined by means of non-polarized and polarized neutron diffraction on single-crystal and powder samples.

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Neutron powder diffraction and transmission electron microscopy studies reveal that the ordered perovskite NaLaMgWO6 has a complex superstructure consisting of a compositional modulation of the A-site cations accompanied by a one-dimensional twinning of the octahedral tilt system.

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A critique of Wang and Liebau's proposed concept of structural valence is presented.

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Extra spots located at one-sixth and one-third positions on 〈110〉p (p = pseudocubic) zone-axis diffraction patterns were attributed to the existence of high-density twins on {111}p pseudocubic planes within the SrRuO3 films rather than to more conventional mechanisms for the generation of superstructure reflections.

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The synthesis and characterization of isomorphous silver(I) complexes [AgX{P(4-MeC6H4)3}3] (X = Br, SCN, ClO4) using single-crystal X-ray diffraction are described and compared with related structures from the literature. The molecular structures of the three complexes are compared using an r.m.s. overlay as well as a half-normal probability plot analysis.

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The dSNAP computer program has been used to classify searches of the Cambridge Structural Database for two ligands commonly found in metal-organic systems.

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Random noise added to theoretical structure factors for a cobalt carbonyl complex is shown to have a large influence on the resulting topological landscape with the potential disappearance of bond-critical points. Atoms in molecules (AIM) analysis of the experimental charge density shows evidence of all the bond-critical points while being highly sensitive to the chosen parameter set.

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The crystal structures of three (S)-4-alkoxo-2-azetidinecarboxylic acids (with alkoxo = decyloxo, dodecyloxo and hexadecyloxo) were solved and refined from synchrotron X-ray powder diffraction data and compared with density-functional theory calculations.


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Although the monohydrates of betaine, cysteic acid and S-4-sulfo-L-phenylalanine all contain hydrate layers, they differ in the orientations of the water molecules. The topologies of S-4-sulfo-L-phenylalanine and betaine monohydrates led us to predict that the former would undergo a phase transition at high pressure, while the latter would not.

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The detailed electron-density distribution of bergenin, an anti-HIV agent, has been determined. It is shown that even a low-order data set measured at room temperature with Ni-filtered Cu Kα radiation and point detection can provide information far beyond the outcomes of an independent atom model refinement.

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An Atoms in Molecules (AIM) analysis of the experimental and theoretical charge density in the title compound confirms the presence of an intramolecular CH⋯π interaction, which was originally suspected on geometrical grounds. The other weak intra- and intermolecular interactions and π-delocalization effects were examined by AIM topological analysis and ellipticity profiles.

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A reversible phase transition into a new polymorph of chlorpropamide on cooling the ∊-form below 200 K has been observed for the first time and followed by single-crystal and powder X-ray diffraction and IR spectroscopy.

short communications


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A survey of recent entries in the Cambridge Structural Database suggests that the percentage of structures described in space groups of inappropriately low symmetry has decreased from about 10% in the early 2000s to less than 5% today for space group Cc, but that for space group P1 it remains close to 8%.

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A low-temperature structure of the title compound was redetermined in the correct space group. The symmetry was determined ab initio by a recently published symmetry-determination algorithm.

addenda and errata


obituaries


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