Acta Crystallographica Section B: Structural Science
Volume 68, Part 3 (June 2012)
Copyright (c) International Union of Crystallography 2012


[Issue Author Index][Volume Author Index]

feature articles


 [Open access]

Acta Cryst. (2012). B68, 215-226
[ doi:10.1107/S0108768112017466 ]

Constrained evolutionary algorithm for structure prediction of molecular crystals: methodology and applications

Q. Zhu, A. R. Oganov, C. W. Glass and H. T. Stokes

Synopsis: A specially designed algorithm to predict the structure of complex crystals consisting of well defined molecular units is presented.

Online 17 May 2012


research papers


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Acta Cryst. (2012). B68, 227-239
[ doi:10.1107/S010876811201419X ]

Structural chemistry of A2MX4 compounds (X = O, F) with isolated tetrahedral anions: search for the densest structure types

V. Nalbandyan and A. Novikova

Synopsis: In three of the nine morphotropic A2MX4 series (nine different tetrahedral anions) the densest structure (spinel) is the stable structure for compounds with A cations of intermediate radius, in contrast to the classical homology rule. In some cases, denser phases have abnormally low overall binding energies.

Online 17 May 2012


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Acta Cryst. (2012). B68, 240-249
[ doi:10.1107/S0108768112008038 ]

Helical screw type magnetic structure of the multiferroic CaMn7O12 with low Cu-doping

W. Slawinski, R. Przenioslo, I. Sosnowska and V. Petrícek

Synopsis: The modulated crystal structure and modulated magnetic ordering of the multiferroic CaCuxMn7-xO12 is studied by analysing neutron and synchrotron-radiation powder diffraction data with a model based on the magnetic superspace group R31'(00[gamma])ts.

Online 4 May 2012


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Acta Cryst. (2012). B68, 250-260
[ doi:10.1107/S0108768112016084 ]

Structure of (Ga2O3)2(ZnO)13 and a unified description of the homologous series (Ga2O3)2(ZnO)2n + 1

Y. Michiue, N. Kimizuka, Y. Kanke and T. Mori

Synopsis: The structure of (Ga2O3)2(ZnO)13 has been determined and a unified description for structures in a homologous series (Ga2O3)2(ZnO)2n + 1 is presented using the (3 + 1)-dimensional superspace formalism.

Online 17 May 2012


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Acta Cryst. (2012). B68, 261-265
[ doi:10.1107/S0108768112012281 ]

Parallel stacking interactions in square-planar transition-metal complexes containing fused chelate and C6-aromatic rings

D. N. Sredojevic, D. Z. Vojislavljevic, Z. D. Tomic and S. D. Zaric

Synopsis: The study of C6-arom-chelate versus C6-arom-C6-arom stacking interactions in the crystal structures of square-planar transition metal complexes showed that the C6-arom ring prefers to form stacking contacts with the chelate rings.

Online 4 May 2012


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Acta Cryst. (2012). B68, 266-274
[ doi:10.1107/S0108768112011226 ]

Phase transition at high pressure in Cu2CO3(OH)2 related to the reduction of the Jahn-Teller effect

M. Merlini, N. Perchiazzi, M. Hanfland and A. Bossak

Synopsis: Malachite, Cu2CO3(OH)2, transforms directly into a rosasite structure at high pressure as a result of the pressure-induced reduction of the Jahn-Teller distortion of CuO6 coordination polyhedra.

Online 4 May 2012


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Acta Cryst. (2012). B68, 275-286
[ doi:10.1107/S0108768112015960 ]

Effect of pressure on crystalline L- and DL-serine: revisited by a combined single-crystal X-ray diffraction at a laboratory source and polarized Raman spectroscopy study

B. A. Zakharov, B. A. Kolesov and E. V. Boldyreva

Synopsis: Information on the effect of pressure on hydrogen bonds, which could be derived from single-crystal X-ray diffraction at a laboratory source and polarized Raman spectroscopy, has been compared.

Online 17 May 2012


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Acta Cryst. (2012). B68, 287-296
[ doi:10.1107/S0108768112015972 ]

Low-temperature phase transition in glycine-glutaric acid co-crystals studied by single-crystal X-ray diffraction, Raman spectroscopy and differential scanning calorimetry

B. A. Zakharov, E. A. Losev, B. A. Kolesov, V. A. Drebushchak and E. V. Boldyreva

Synopsis: A low-temperature reversible phase transition at 220-230 K in glycine-glutaric acid co-crystals changes the conformation of every second glutaric acid molecule, but preserves the topology of the hydrogen-bond network, despite changes to the hydrogen-bond lengths and the space-group symmetry.

Online 17 May 2012


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Acta Cryst. (2012). B68, 297-304
[ doi:10.1107/S0108768112010993 ]

Relation between photochromic properties and molecular structures in salicylideneaniline crystals

K. Johmoto, T. Ishida, A. Sekine, H. Uekusa and Y. Ohashi

Synopsis: Salicylideneaniline crystals exhibit photochromism under the following conditions: the dihedral angle between the two terminal benzene rings is greater than 30° and there is no intra- or intermolecular steric hindrance to inhibit a pedal motion within the crystal.

Online 4 May 2012


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Acta Cryst. (2012). B68, 305-312
[ doi:10.1107/S0108768112014711 ]

Voronoi-Dirichlet tesselation as a tool for investigation of polymorphism in molecular crystals with CwHxNyOz composition and photochromic properties

V. N. Serezhkin, L. B. Serezhkina and A. V. Vologzhanina

Synopsis: A relationship between photochromism and non-bonded interactions was investigated with the Voronoi-Dirichlet approach. Crystal structures of five sets of conformational polymorphs with the CwHxNyOz composition have been taken into account. It was demonstrated that each polymorph is characterized by a unique set of inter- and intramolecular contacts.

Online 17 May 2012


short communications


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Acta Cryst. (2012). B68, 313-317
[ doi:10.1107/S0108768112017831 ]

Invariom modeling of ceftazidime pentahydrate: molecular properties from a 200 second synchrotron microcrystal experiment

C. J. Schürmann, K. Pröpper, T. Wagner and B. Dittrich

Synopsis: The structure of ceftadizime pentahydrate was determined from a 200 s experiment with synchrotron radiation. Combined with invariom refinement for rapid property calculation, high-throughput electron-density studies of hundreds of compounds become feasible.

Online 17 May 2012


 

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Acta Cryst. (2012). B68, 318-320
[ doi:10.1107/S0108768112020289 ]

Exact solution of the bond-valence sum rule for a set of coordination shells

V. Sidey

Synopsis: The calculation scheme for determining the bond-valence parameters (r0 and b) resulting in the exact solution of the bond-valence sum rule for a given set of coordination shells is presented.

Online 17 May 2012


books received


 [Open access]

Acta Cryst. (2012). B68, 321
[ doi:10.1107/S0108768112018551 ]

Symmetriebeziehungen zwischen verwandten Kristallstrukturen

Online 17 May 2012