Acta Crystallographica Section B

Structural Science

Volume 67, Part 6 (December 2011)



[Issue Author Index][Volume Author Index]
[Cover illustration] Cover illustration: The cover picture highlights an artefact in the electrostatic potential of the macrolide antibiotic roxithromycin as derived via multipole refinement of X-ray diffraction data.  Ignoring the hydrogen disorder (left) in the oxime chain leads to a falsely positive electrostatic potential there as a result of the multipole model's being flexible enough to fit the averaged electron density.  If the invariom formalism, which uses theoretical electron density, is applied to the disordered region (right) the artefact disappears.  A procedure for obtaining reliable electron density distributions in the presence of disorder has been proposed [Holstein et al. (2010). Acta Cryst. B66, 568-577].

research papers


thumbnail of article figure

[HTML version][PDF version][CIF][3d view][Structure Factors]  [Buy article online]

Acta Cryst. (2011). B67, 447-454  [ doi:10.1107/S0108768111044867 ]

Dynamic orientational disorder in crystals of fluoroelpasolites, structural refinement of (NH4)3AlF6, (NH4)3TiOF5 and Rb2KTiOF5

A. A. Udovenko and N. M. Laptash

Synopsis: Electron-density profiles indicate the cations to be tetrahedrally shifted from the 8c position into the 32f site of the Fm3m unit cell as a new feature of the fluoroelpasolite structure refinement.

Online 17 November 2011


thumbnail of article figure

[HTML version][PDF version][CIF][3d view][Powder data file][Supplementary Material]  [Buy article online]

Acta Cryst. (2011). B67, 455-460  [ doi:10.1107/S0108768111039759 ]

Structure of LaTi2Al9O19 and reanalysis of the crystal structure of La3Ti5Al15O37

M. Kasunic, A. Meden, S. D. Skapin, D. Suvorov and A. Golobic

Synopsis: The crystal structure of LaTi2Al9O19 determined by X-ray powder diffraction is presented together with its dielectric properties. The structure of La3Ti5Al15O37 is critically reviewed.

Online 13 October 2011


thumbnail of article figure

[HTML version][PDF version][CIF][3d view][Powder data files]  [Buy article online]

Acta Cryst. (2011). B67, 461-466  [ doi:10.1107/S010876811103936X ]

The not so simple cubic structure of PbZr1 - xTixO3 (PZT): complex local structural effects in perovskites

N. Zhang, H. Yokota, A. M. Glazer and P. A. Thomas

Synopsis: High-resolution neutron diffraction of the important piezoelectric lead zirconate titanate (PZT) has found that oxygen disorder exists well into the cubic phase.

Online 17 November 2011


thumbnail of article figure

[HTML version][PDF version][CIF][3d view][Structure Factors]  [AD]  [Buy article online]

Acta Cryst. (2011). B67, 467-475  [ doi:10.1107/S0108768111041759 ]

Water channel structure of bassanite at high air humidity: crystal structure of CaSO4·0.625H2O

H. Schmidt, I. Paschke, D. Freyer and W. Voigt

Synopsis: In the presence of high relative air humidity the crystal structure of CaSO4·0.5H2O transforms due to the incorporation of additional water of hydration. The crystal structure of CaSO4·0.625H2O was solved by single-crystal X-ray diffraction at 298 K with 75% relative air humidity.

Online 17 November 2011


thumbnail of article figure

[HTML version][PDF version][CIF][3d view][Structure Factors][Supplementary Material]  [Open access]

Acta Cryst. (2011). B67, 476-485  [ doi:10.1107/S0108768111042005 ]

Stacking faults and superstructures in a layered brownmillerite

H. Krüger, S. Stöber, T. Welberry, R. Withers and J. Fitz Gerald

Synopsis: Stacking faults in Ca4Fe2Mn0.5Ti0.5O9 have been examined using X-ray diffraction and high-resolution transmission electron microscopy. Electron diffraction revealed two superstructures with ordered stacking sequences.

Online 17 November 2011


thumbnail of article figure

[HTML version][PDF version][CIF][3d view][Structure Factors][Supplementary Material]  [Buy article online]

Acta Cryst. (2011). B67, 486-498  [ doi:10.1107/S0108768111045897 ]

[Ni(H2O)6](NO3)2·(15-crown-5)·2H2O: three phase transitions and an intermediate modulated phase stable over a range of ca 40 K

M. A. Siegler, X. Hao, S. Parkin and C. P. Brock

Synopsis: The structure of single-crystal [Ni(H2O)6](NO3)2·(15-crown-5)·2H2O has been studied in the range 90-308 K in intervals of [less-than or equal to] 10 K as the crystal passed through three phase transitions. An unusual intermediate, modulated phase described in a commensurate approximation (Z' = 7) has been characterized.

Online 17 November 2011


thumbnail of article figure

[HTML version][PDF version][CIF][3d view][Structure Factors][Supplementary Material]  [Buy article online]

Acta Cryst. (2011). B67, 499-507  [ doi:10.1107/S0108768111045113 ]

Structural study of piracetam polymorphs and cocrystals: crystallography redetermination and quantum mechanics calculations

A. Tilborg, D. Jacquemin, B. Norberg, E. Perpète, C. Michaux and J. Wouters

Synopsis: A joint theoretical and experimental investigation of the structure of piracetam, in which the conformational space of piracetam is explored by a scan of the two dihedral angles and predicted conformations with intramolecular hydrogen bonds are compared with CSD geometries. Single crystals and the structure of piracetam are obtained and statistical comparison with CSD forms shows only three dihedral angle families.

Online 17 November 2011


thumbnail of article figure

[HTML version][PDF version][CIF][3d view][Structure Factors]  [Open access]

Acta Cryst. (2011). B67, 508-515  [ doi:10.1107/S0108768111038560 ]

Determining the structure of a benzene7.2-silicalite-1 zeolite using a single-crystal X-ray method

N. Kamiya, W. Iwama, T. Kudo, T. Nasuno, S. Fujiyama, K. Nishi and Y. Yokomori

Synopsis: An orthorhombic benzene-silicalite-1 single crystal was obtained from a monoclinic twin crystal, and the structure was determined by a single-crystal method for the first time.

Online 13 October 2011


thumbnail of article figure

[HTML version][PDF version][Video data file]  [Buy article online]

Acta Cryst. (2011). B67, 516-524  [ doi:10.1107/S0108768111037542 ]

Diffuse scattering resulting from macromolecular frustration

T. R. Welberry, A. P. Heerdegen, D. C. Goldstone and I. A. Taylor

Synopsis: Distinctive diffuse scattering in the form of diffuse rings around Bragg positions has been observed in the diffraction patterns of a crystal of the N-terminal fragment of the Gag protein from Feline Foamy Virus. It is shown that these are caused by geometric frustration as molecules try to pack on the triangular b-c mesh of the space group P6122.

Online 13 October 2011


thumbnail of article figure

[HTML version][PDF version][CIF][3d view][Structure Factors][Supplementary Material]  [Buy article online]

Acta Cryst. (2011). B67, 525-534  [ doi:10.1107/S0108768111037487 ]

Crystal packing and melting temperatures of small oxalate esters: the role of C-H...O hydrogen bonding

S. Joseph, R. Sathishkumar, S. Mahapatra and G. R. Desiraju

Synopsis: Dialkyl oxalates are cryocrystallized and the crystal structures have been analysed. The distinctive nature of two oxalates that are solid at room temperature is rationalized on the basis of C-H...O interactions.

Online 13 October 2011


thumbnail of article figure

[HTML version][PDF version][Supplementary Material]  [Open access]

Acta Cryst. (2011). B67, 535-551  [ doi:10.1107/S0108768111042868 ]

Towards crystal structure prediction of complex organic compounds - a report on the fifth blind test

D. A. Bardwell, C. S. Adjiman, Y. A. Arnautova, E. Bartashevich, S. X. M. Boerrigter, D. E. Braun, A. J. Cruz-Cabeza, G. M. Day, R. G. Della Valle, G. R. Desiraju, B. P. van Eijck, J. C. Facelli, M. B. Ferraro, D. Grillo, M. Habgood, D. W. M. Hofmann, F. Hofmann, K. V. J. Jose, P. G. Karamertzanis, A. V. Kazantsev, J. Kendrick, L. N. Kuleshova, F. J. J. Leusen, A. V. Maleev, A. J. Misquitta, S. Mohamed, R. J. Needs, M. A. Neumann, D. Nikylov, A. M. Orendt, R. Pal, C. C. Pantelides, C. J. Pickard, L. S. Price, S. L. Price, H. A. Scheraga, J. van de Streek, T. S. Thakur, S. Tiwari, E. Venuti and I. K. Zhitkov

Synopsis: The results of the fifth blind test of crystal structure prediction, which show important success with more challenging large and flexible molecules, are presented and discussed.

Online 17 November 2011


thumbnail of article figure

[HTML version][PDF version][CIF][3d view][Structure Factors][Supplementary Material]  [Buy article online]

Acta Cryst. (2011). B67, 552-559  [ doi:10.1107/S0108768111043138 ]

The whole range of hydrogen bonds in one crystal structure: neutron diffraction and charge-density studies of N,N-dimethylbiguanidinium bis(hydrogensquarate)

M.-D. Serb, R. Wang, M. Meven and U. Englert

Synopsis: Neutron and high-resolution X-ray diffraction experiments at 100 K have been used to derive the precise geometry and the electron density of a wide range of X-H...O interactions in the title compound. The shortest O-H...O bond does not follow the trend of the remaining hydrogen bonds: it is significantly more symmetric, and energy density criteria support the concept of an interaction with intermediate character between covalent and closed-shell.

Online 17 November 2011


thumbnail of article figure

[HTML version][PDF version][CIF][3d view][Structure Factors]  [Buy article online]

Acta Cryst. (2011). B67, 560-568  [ doi:10.1107/S0108768111037311 ]

Molecular origins of commercial laser dye functionality in azacoumarins and 2-quinolones: LD 425, LD 489 and LD 473

X. Liu, J. M. Cole, P. G. Waddell and T.-C. Lin

Synopsis: The structural data of two azacoumarins, LD 425 and LD 489, and one 2-quinolone, LD 473, are reported. Bond-length patterns and characteristic spectral blue shifts in these compounds are examined using resonance theory and structural comparisons with their coumarin analogues.

Online 13 October 2011


thumbnail of article figure

[HTML version][PDF version][CIF][3d view][Structure Factors][Supplementary Material]  [Buy article online]

Acta Cryst. (2011). B67, 569-581  [ doi:10.1107/S0108768111041747 ]

Experimental and theoretical electron-density study of three isoindole derivatives: topological and Hirshfeld surface analysis of weak intermolecular interactions

L. Checinska, S. Grabowsky, M. Malecka, A. J. Rybarczyk-Pirek, A. Józwiak, C. Paulmann and P. Luger

Synopsis: Weak intermolecular contacts of C-H...C([pi]), C,N([pi])...C,N([pi]) and H...H types occurring in crystals of isoindole derivatives were analysed in terms of topological electron-density parameters and Hirshfeld surfaces derived from high-resolution X-ray diffraction experiments.

Online 17 November 2011


Copyright © International Union of Crystallography
IUCr Webmaster