Acta Crystallographica Section B

Structural Science

Volume 64, Part 5 (October 2008)



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[Cover 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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Acta Cryst. (2008). B64, 521-526  [ doi:10.1107/S0108768108021125 ]

Structure of Ga2O3(ZnO)6: a member of the homologous series Ga2O3(ZnO)m

Y. Michiue, N. Kimizuka and Y. Kanke

Synopsis: The structure of Ga2O3(ZnO)6 is clarified using single-crystal X-ray diffraction techniques, and general rules for constructing structures in the homologous series Ga2O3(ZnO)m are presented.

Online 16 September 2008


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Acta Cryst. (2008). B64, 527-533  [ doi:10.1107/S0108768108021289 ]

Orientational disorder and phase transitions in crystals of (NH4)2NbOF5

A. A. Udovenko and N. M. Laptash

Synopsis: Structural phase transitions in a crystal of (NH4)2NbOF5 are the consequence of dynamic changes in its structural units as the temperature decreases. Using X-ray diffraction, it is possible to identify O and F atoms in the disordered structure of (NH4)2NbOF5 as a result of its dynamic nature.

Online 6 September 2008


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Acta Cryst. (2008). B64, 534-549  [ doi:10.1107/S0108768108026542 ]

5d and 4f electron configuration of CeB6 at 340 and 535 K

R. Makita, K. Tanaka and Y. Onuki

Synopsis: The electron-density distribution of CeB6 was measured at 340 and 535 K to determine the electron configuration of 4f and 5d orbitals, and the electron transfer from B to Ce.

Online 16 September 2008


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Acta Cryst. (2008). B64, 550-557  [ doi:10.1107/S0108768108026384 ]

[Rh(C7H8)(PPh3)Cl]: an experimental charge-density study

H. A. Sparkes, S. K. Brayshaw, A. S. Weller and J. A. K. Howard

Synopsis: An accurate experimental charge-density analysis is reported for the title compound, in order to gain further insights into the bonding situation in rhodium complexes. Particular focus is given to examining the interactions between the rhodium metal centre and the norbornadiene cage.

Online 16 September 2008


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Acta Cryst. (2008). B64, 558-566  [ doi:10.1107/S0108768108027353 ]

From six- to five-coordinated SbIII in [(CH3)3PH]3[Sb2Cl9]: transition pathways from single-crystal X-ray diffraction

A. Gagor, M. Wojtas, A. Pietraszko and R. Jakubas

Synopsis: [(CH3)3PH]3[Sb2Cl9] experiences four phase transitions which were found by means of calorimetry, thermogravimetry and X-ray diffraction. The crystal structure was solved in the space group P63/mmc at 382 K (phase I), Pnam at 295 K (phase II) and Pna21 at 175 K (phase V).

Online 16 September 2008


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Acta Cryst. (2008). B64, 567-572  [ doi:10.1107/S0108768108018223 ]

Redetermination of the structure and dielectric properties of bis(thiourea) pyridinium iodide - a new ferroelectric inclusion compound

H. Maluszynska, P. Czarnecki, Z. Fojud and J. Wasicki

Synopsis: The structures of three phases of the inclusion compound bis(thiourea) pyridinium iodide have been determined. Ferroelectric properties have been found in the low-temperature phases.

Online 6 September 2008


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Acta Cryst. (2008). B64, 573-582  [ doi:10.1107/S0108768108025093 ]

Polymorphism in cyclohexanol

R. M. Ibberson, S. Parsons, D. R. Allan and A. M. T. Bell

Synopsis: The crystal structures of phase II and the metastable phases III' and III of cyclohexanol, C6H11OH, have been determined using high-resolution neutron powder and single-crystal X-ray diffraction techniques. Phase II crystallizes in a tetragonal structure, space group P\bar 42_1c, characterized by a hydrogen-bonded tetrameric ring motif. Phases III' and III are monoclinic, space groups P21/c and Pc, respectively, with molecules linked via hydrogen-bonded chains.

Online 6 September 2008


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Acta Cryst. (2008). B64, 583-588  [ doi:10.1107/S0108768108019460 ]

Hydrogen-bond patterns and the structures of 1,4-cyclohexanediol: 2:1 cis:trans-1,4-cyclohexanediol

J. H. Loehlin, M. Lee and C. M. Woo

Synopsis: Two determinations of the structure of trans/cis co-crystals of 1,4-cyclohexanediol are reported, and their intermolecular hydrogen-bond patterns described using the graph-set model.

Online 6 September 2008


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Acta Cryst. (2008). B64, 589-595  [ doi:10.1107/S0108768108015103 ]

Orientational ordering in the low-temperature stable phases of deuterated thiophene

F. Damay, J. Rodríguez-Carvajal, D. André, F. Dunstetter and H. Szwarc

Synopsis: A structural investigation of thiophene between 155 and 1.5 K by neutron diffraction is reported.

Online 15 September 2008


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Acta Cryst. (2008). B64, 596-609  [ doi:10.1107/S0108768108019915 ]

N6-Substituted 2-amino-4-chloro-5-formylpyrimidines: puckered versus planar pyrimidine rings, and hydrogen-bonded aggregation in zero, one, two and three dimensions

J. Cobo, J. Trilleras, J. Quiroga, A. Marchal, M. Nogueras, J. N. Low and C. Glidewell

Synopsis: In N6-substituted 2-amino-4-chloro-5-formylpyrimidines, with three adjacent substituents on the pyrimidine ring, this ring can be planar or else puckered towards boat, screw-boat or twist-boat conformations. The supramolecular aggregation is dominated by N-H...N hydrogen bonds and the resulting hydrogen-bonded structures can be finite (zero-dimensional) or one-, two- or three-dimensional.

Online 15 September 2008


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Acta Cryst. (2008). B64, 610-622  [ doi:10.1107/S0108768108019903 ]

Anhydrous versus hydrated N4-substituted 1H-pyrazolo[3,4-d]pyrimidine-4,6-diamines: hydrogen bonding in two and three dimensions

J. Trilleras, J. Quiroga, J. Cobo, A. Marchal, M. Nogueras, J. N. Low and C. Glidewell

Synopsis: N4-substituted 1H-pyrazolo[3,4-d]pyrimidine-4,6-diamines can crystallize either in anhydrous form or as stoichiometric hemihydrates or monohydrates, and the hydrogen-bonded structures they form may be either two- or three-dimensional. Those examples which crystallize as hemihydrates adopt very similar supramolecular structures despite a wide diversity of N4-substituents and space groups.

Online 15 September 2008


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Acta Cryst. (2008). B64, 623-632  [ doi:10.1107/S0108768108026645 ]

Polymorphism of urea-barbituric acid co-crystals

M. Gryl, A. Krawczuk and K. Stadnicka

Synopsis: The existence of different polymorphs for urea and barbituric acid co-crystals is explained on the basis of the resonance properties of barbituric acid (mesomeric effect). Higher-level graph-set analysis revealed a specific behaviour of the hydrogen-bond systems responsible for the mutual spatial arrangement of the structural components in the polymorphs.

Online 16 September 2008


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Acta Cryst. (2008). B64, 633-643  [ doi:10.1107/S0108768108023264 ]

A room-temperature X-ray diffuse scattering study of form (II) of the trimorphic molecular system p-(N-methylbenzylidene)-p-methylaniline

A. G. Beasley, T. R. Welberry, D. J. Goossens and A. P. Heerdegen

Synopsis: Strong and highly structured diffuse scattering has been observed for form (II) of the trimorphic molecular system p-(N-methylbenzylidene)-p-methylaniline. Analysis using Monte Carlo simulation techniques has revealed highly correlated molecular motions, suggesting possible mechanisms for the transformation to the other polymorphs.

Online 15 September 2008


book reviews


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Acta Cryst. (2008). B64, 644  [ doi:10.1107/S0108768108025986 ]

Crystallography of Modular Materials. Vol. 15, IUCr Monographs on Crystallography

Online 16 September 2008