issue contents

Journal logoSTRUCTURAL SCIENCE
CRYSTAL ENGINEERING
MATERIALS
ISSN: 2052-5206

December 2008 issue

Highlighted illustration

Cover illustration: The cover picture shows the strong and highly structured diffuse scattering from polymorph (II) of N-(p-methylbenzylidene)-p-methylaniline (MeMe) and indicates strongly correlated molecular motion not apparent from the Bragg analysis. Unlike polymorphs (I) and (III), which are disordered, polymorph (II) appears from Bragg scattering to be a perfectly normal ordered molecular crystal. The section of diffuse scattering data shown is part of a full three-dimensional data set recorded on beamline 1-ID-C at the Advanced Photon Source at Argonne, Illinois. Courtesy of Professor T. R. Welberry and Andrew Beasley.

research papers


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Orientational disorder in Rb2WO2F4 and (NH4)2WO2F4 have been compared. In the ammonium compound, but not in the rubidium compound, it was possible to distinguish between O and F atoms in the distorted cis-[WO2F4]2 octahedron and to determine its true geometry owing to the dynamic nature of the disorder. The ammonium compound undergoes phase transitions of the order–disorder type when the temperature is lowered but the rubidium compound does not.

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The mixed-valence vanadate α-YbV4O8 undergoes an isosymmetrical phase transition at 70 K. The transition is accompanied by a paramagnetic–paramagnetic anomaly and leads to complete charge ordering.

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The crystal structure of the synthetic cobalt olivine, Co2SiO4, is determined by means of single-crystal neutron diffraction and X-ray powder diffraction in the temperature range 300–2.5 K.

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The ordered P2/c structure of (Ba,Sr)4Ti6Si4O24·H2O was obtained first by solving the disordered Cmmm structure by single-crystal X-ray diffraction data and then applying the order–disorder theory.

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A structural phase transition is shown around 400 K for the thermoelectric lamellar misfit cobalt oxide [Ca2CoO3][CoO2]1.62. This transition is related to a rearrangement of the central [CoO] layer of the [Ca2CoO3] slab.

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The use of the superspace formalism is extended to the analysis and refinement of homologous series of modular structures, with two symmetry-related modules. This approach has been successfully applied to the lillianite homologous series.

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A total of 186 complex halide systems were collected; the formabilities of ABX3 (X = F, Cl, Br and I) halide perovskites were investigated using the empirical structure map, which was constructed by Goldschmidt's tolerance factor and the octahedral factor.

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The single-crystal X-ray diffraction study of Ce10W22O81 and powder X-ray diffraction experiments on Ce10W22O81 and Nd10W22O81 show that the true space group of these phases is Pbnm.

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The crystal structure of mordenite zeolite hosting guest molecules of p-N,N-dimethylnitroaniline has been solved by synchrotron powder diffraction. The localization of the molecules in the channel system and the possible stabilizing interactions are discussed and compared with literature results.

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The yellow compound [Ni(H2O)2(15C5)](NO3)2, 15C5 = 15-crown-5, has been made by heating pale green crystals of [Ni(H2O)6](NO3)2·15C5·2H2O to over 350 K. While trying to obtain the Ni2+ ion inside the crown ligand five other compounds were prepared, all of which have surprisingly complicated crystal structures organized by the hydrogen-bonded motif ⋯15C5⋯H2O—NiII—OH2⋯15C5⋯H2O—NiII—OH2⋯.

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Structures of five more phases of the [M(H2O)2(15-crown-5)](NO3)2 (M = Mg, Mn, Fe, Co, Ni, Cu and Zn) family have been determined. All stable phases whose existence at accessible temperatures is indicated by differential scannng calorimetry have now been characterized.

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Three L-hydroxylysine structures have been determined at 100 K by single-crystal X-ray diffraction to high resolution using a laboratory or synchrotron source. Visualizations of anisotropic displacement parameter (ADP) differences with the program PEANUT indicate the high quality of the invariom ADPs, which are similar to ADPs from a free multipole refinement and superior to ADPs from IAM and high-order IAM refinements.

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The crystal structures of four derivatives of arylsulfonylalkanoids obtained in the course of the syntheses of new artificial sweeteners have been determined and compared with other tetrazole-containing structures identified from a CSD search. The lack of a sweet taste of the four tetrazole derivatives is tentatively explained.

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The polymorphism of 1,3-dilauroyl-2-oleoylglycerol has been studied and the structures of the \beta ^{\prime}_1-2, β′-3 and β2-3 polymorphs have been solved from high-resolution powder diffraction data.

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The crystal structures of co-crystals of two systems of chiral carboxylic acids, optically active and racemic 2-phenylpropionic acid and 2-phenylbutyric acid, with isonicotinamide are reported to investigate the effects of the chirality of the chiral carboxylic acids on the melting point of the co-crystal complexes.

addenda and errata


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