Structural Science

 

Acta Cryst. (2009). B65, 659-663  [ doi:10.1107/S0108768109041019 ]

Growth and single-crystal refinement of phase-III potassium nitrate, KNO₃

E. J. Freney, L. A. J. Garvie, T. L. Groy and P. R. Buseck

Synopsis: 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.

Online 16 November 2009

 

Acta Cryst. (2009). B65, 664-675  [ doi:10.1107/S0108768109042499 ]

Magnetic behaviour of synthetic Co₂SiO₄

A. Sazonov, M. Meven, V. Hutanu, G. Heger, T. Hansen and A. Gukasov

Synopsis: 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.

Online 16 November 2009

 

Acta Cryst. (2009). B65, 676-683  [ doi:10.1107/S0108768109032728 ]

Octahedral tilt twinning and compositional modulation in NaLaMgWO₆

G. King, S. Garcia-Martin and P. M. Woodward

Synopsis: 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.

Online 27 October 2009

 

Acta Cryst. (2009). B65, 684-693  [ doi:10.1107/S0108768109034417 ]

On the valences of bonds in the oxycomplexes of Sn²⁺

I. D. Brown

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

Online 27 October 2009

 

Acta Cryst. (2009). B65, 694-698  [ doi:10.1107/S0108768109045121 ]

(111)_p microtwinning in SrRuO₃ thin films on (001)_p LaAlO₃

Y. Han, I. M. Reaney, D. S. Tinberg and S. Trolier-McKinstry

Synopsis: 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.

Online 16 November 2009

 

Acta Cryst. (2009). B65, 699-706  [ doi:10.1107/S0108768109036404 ]

Isomorphism in monomeric 1:3 complexes of silver(I) salts with tri-p-tolylphosphine

B. Omondi, G. J. S. Venter, A. Roodt and R. Meijboom

Synopsis: 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.

Online 16 November 2009

 

Acta Cryst. (2009). B65, 707-714  [ doi:10.1107/S0108768109038051 ]

Cluster analyses of metal-organic fragments using the dSNAP software

A. Collins, C. C. Wilson and C. J. Gilmore

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

Online 16 November 2009

 

Acta Cryst. (2009). B65, 715-723  [ doi:10.1107/S0108768109045091 ]

Experimental and theoretical charge-density study of a tetranuclear cobalt carbonyl complex

J. Overgaard, J. A. Platts and B. B. Iversen

Synopsis: 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.

Online 16 November 2009

 

Acta Cryst. (2009). B65, 724-730  [ doi:10.1107/S0108768109036386 ]

Molecular and crystalline structures of three (S)-4-alkoxycarbonyl-2-azetidinones containing long alkyl side chains from synchrotron X-ray powder diffraction data

L. E. Seijas, A. J. Mora, G. E. Delgado, F. López-Carrasquero, M. E. Báez, M. Brunelli and A. N. Fitch

Synopsis: 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.

Online 16 November 2009

 

Acta Cryst. (2009). B65, 731-748  [ doi:10.1107/S0108768109039469 ]

Comparison of the effects of pressure on three layered hydrates: a partially successful attempt to predict a high-pressure phase transition

R. D. L. Johnstone, A. R. Lennie, S. Parsons, E. Pidcock and J. E. Warren

Synopsis: 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.

Online 16 November 2009

 

Acta Cryst. (2009). B65, 749-756  [ doi:10.1107/S0108768109046060 ]

How to easily replace the independent atom model - the example of bergenin, a potential anti-HIV agent of traditional Asian medicine

B. Dittrich, M. Weber, R. Kalinowski, S. Grabowsky, C. B. Hübschle and P. Luger

Synopsis: 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 K radiation and point detection can provide information far beyond the outcomes of an independent atom model refinement.

Online 16 November 2009

 

Acta Cryst. (2009). B65, 757-769  [ doi:10.1107/S010876810903273X ]

Weak intra- and intermolecular interactions in a binaphthol imine: an experimental charge-density study on (±)-8'-benzhydrylideneamino-1,1'-binaphthyl-2-ol

L. J. Farrugia, P. Kocovský, H. M. Senn and S. Vyskocil

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

Online 27 October 2009

 

Acta Cryst. (2009). B65, 770-781  [ doi:10.1107/S010876810903290X ]

A conformational polymorphic transition in the high-temperature -form of chlorpropamide on cooling: a new '-form

T. N. Drebushchak, Y. A. Chesalov and E. V. Boldyreva

Synopsis: 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.

Online 27 October 2009

 

Acta Cryst. (2009). B65, 782-783  [ doi:10.1107/S0108768109046448 ]

Space groups P1 and Cc: how are they doing?

R. E. Marsh

Synopsis: 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%.

Online 16 November 2009

 

Acta Cryst. (2009). B65, 784-786  [ doi:10.1107/S0108768109042608 ]

Towards a more reliable symmetry determination from powder diffraction: a redetermination of the low-temperature structure of 4-methylpyridine-N-oxide

L. Palatinus and F. Damay

Synopsis: 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.

Online 16 November 2009

 

Acta Cryst. (2009). B65, 787  [ doi:10.1107/S0108768109044899 ]

[Ru(py)₄Cl(NO)](PF₆)₂·0.5H₂O: a model system for structural determination and ab initio calculations of photo-induced linkage NO isomers. Erratum

B. Cormary, I. Malfant, L. Valade, M. Buron-Le Cointe, L. Toupet, T. Todorova, B. Delley, D. Schaniel, N. Mockus, T. Woike, K. Fejfarová, V. Petrícek and M. Dusek

Synopsis: Erratum to Cormary et al. (2009), Acta Cryst. B65, 612-623.

Online 16 November 2009

 

Acta Cryst. (2009). B65, 788-790  [ doi:10.1107/S0108768109047533 ]

Clara Brink Shoemaker (1921-2009)

S. C. Abrahams and K. Hedberg

Online 16 November 2009