[IUCr 2014 Congress]

Acta Crystallographica Section B

Structural Science, Crystal Engineering and Materials

Volume 69, Part 5 (October 2013)



[Issue Author Index][Volume Author Index]
[Cover illustration] Cover illustration: Reduction of volumes of the voids in the crystal structures of DL-alanine and L-alanine on application of 6 GPa of pressure. Yellow voids are shown within the ball-and-stick structure models. The molecules as well as the topologies and symmetries of their packings are preserved over the whole pressure range of 0-6 GPa. See Fig. 4 in Tumanov & Boldyreva [(2012), Acta Cryst. B68, 412-423].

research papers


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Acta Cryst. (2013). B69, 419-425  [ doi:10.1107/S2052519213021271 ]

Bond-valence model for metal cluster compounds. I. Common lattice strains

E. Levi, D. Aurbach and O. Isnard

Synopsis: The bond-valence model used previously only for common ionic solids was adapted to (TM)6-chalcohalides, Mx(TM)6Ly (TM = transition metal in the cluster: Nb, Mo, W and Re; L = chalcogen and/or halogen ligands; M = counter-cation). This paper is devoted to the strains around M cations as one of the sources of the valence violations in cluster compounds.

Online 19 September 2013


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Acta Cryst. (2013). B69, 426-438  [ doi:10.1107/S2052519213021283 ]

Bond-valence model for metal cluster compounds. II. Matrix effect

E. Levi, D. Aurbach and O. Isnard

Synopsis: The bond-valence model used previously only for common ionic solids was adapted to (TM)6-chalcohalides, Mx(TM)6Ly (TM = transition metal in the cluster: Nb, Mo, W and Re; L = the chalcogen and/or halogen ligands; M = counter-cation). This paper gives a detailed description of the matrix effect.

Online 19 September 2013


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Acta Cryst. (2013). B69, 439-445  [ doi:10.1107/S2052519213020514 ]

Tolerance factor for pyrochlores and related structures

R. Mouta, R. X. Silva and C. W. A. Paschoal

Synopsis: In this work we discuss the concept of tolerance factors for pyrochlores and related structures. We proposed a new form to calculate the tolerance factors for these structures and correlated the tolerance factor with some physical properties.

Online 13 September 2013


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Acta Cryst. (2013). B69, 446-456  [ doi:10.1107/S2052519213023087 ]

Effect of lone-pair stereoactivity on polyhedral volume and structural flexibility: application to TeIVO6 octahedra

A. G. Christy and S. J. Mills

Synopsis: The volumes of 40 TeIVO6 coordination polyhedra studied are 10.3-23.7 Å3, compared with the 12.83 Å3 expected for a regular octahedron. The anions lie close to a spherical surface whose radius varies with the degree of lone-pair localization; 95% of the variation in polyhedron volume is due to a change in both sphere radius and the uniformity of oxygen distribution over the sphere.

Online 19 September 2013


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Acta Cryst. (2013). B69, 457-464  [ doi:10.1107/S2052519213021635 ]

TiGePt - a study of Friedel differences

S.-V. Ackerbauer, H. Borrmann, H.-B. Bürgi, H. D. Flack, Y. Grin, A. Linden, L. Palatinus, W. B. Schweizer, R. Warshamanage and M. Wörle

Synopsis: By the use of Rmerge factors on Friedel-difference intensities and the D-Patterson function, the structure of the intermetallic compound TiGePt is shown to be non-centrosymmetric.

Online 19 September 2013


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Acta Cryst. (2013). B69, 465-473  [ doi:10.1107/S2052519213021155 ]

X-ray diffraction: a powerful tool to probe and understand the structure of nanocrystalline calcium silicate hydrates

S. Grangeon, F. Claret, Y. Linard and C. Chiaberge

Synopsis: The structure of nanocrystalline calcium silicate hydrates (C-S-H) was studied using X-ray diffraction and literature data. It is proposed that C-S-H of Ca/Si ratio ranging between ~ 0.6 and ~ 1.7 can be described as nanocrystalline tobermorite affected by turbostratic disorder. The broadening and shift of the basal reflection positioned between ~ 13.5 and ~ 11.2 Å (depending on the Ca/Si ratio) arises from nanocrystallinity and possibly from an interstratification phenomenon.

Online 19 September 2013


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Acta Cryst. (2013). B69, 474-479  [ doi:10.1107/S2052519213021234 ]

Polytypes and twins in the diamond-lonsdaleite system formed by high-pressure and high-temperature treatment of graphite

B. Kulnitskiy, I. Perezhogin, G. Dubitsky and V. Blank

Synopsis: Twins and polytypes in diamond and lonsdaleite nanoparticles were studied by high-resolution transmission electron microscopy, and the mechanisms of their appearance were proposed. Coherent and incoherent twin boundaries were observed in nanoparticles.

Online 13 September 2013


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Acta Cryst. (2013). B69, 480-489  [ doi:10.1107/S2052519213024068 ]

Two- and three-dimensional assembled structures constructed from amidate-bridged paddlewheel complexes with group 6 oxometallate ions

M. Ebihara and Y. Fuma

Synopsis: Monocationic amidate-bridged dimetal complexes reacted with dianionic group 6 metallate ions to form two-dimensional square-sheet or three-dimensional diamondoid structures depending on the alkyl group of the amidate ligands.

Online 19 September 2013


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Acta Cryst. (2013). B69, 490-495  [ doi:10.1107/S2052519213023713 ]

Structure and magnetic properties of a new iron(II) citrate coordination polymer

T. Birsa Celic, Z. Jaglicic, K. Lazar and N. Zabukovec Logar

Synopsis: The three-dimensional structure of a hydrothermally synthesized new iron citrate compound, [Fe(H2cit)(H2O)]n, which is built up from the chains of corner-sharing FeO6 octahedra that are further connected through citrate anions, was solved by single-crystal X-ray diffraction. Thermal and magnetic properties of material were investigated by TG, HT-XRD, Mossbauer and magnetic susceptibility analyses.

Online 19 September 2013


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Acta Cryst. (2013). B69, 496-508  [ doi:10.1107/S205251921301782X ]

C6H4S2AsCl: description and interpretation of an incommensurately modulated molecular crystal structure

R. C. Bakus II, D. A. Atwood, S. Parkin, C. P. Brock and V. Petricek

Synopsis: A modulated molecular structure has been refined in (3 + 1)-dimensional superspace and also as two different Z' = 17 commensurate approximations. The incommensurate modulation can be understood as relieving packing problems in several different directions.

B-IncStrDB reference: 8082ERT5uS

Online 13 September 2013


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Acta Cryst. (2013). B69, 509-513  [ doi:10.1107/S2052519213018605 ]

Allotwinning in a molecular crystal: (1R,3S)-dimethyl 2-oxocyclohexane-1,3-dicarboxylate

A. Jahangiri, A. Fleckhaus, S. Lidin and D. Strand

Synopsis: The crystal structures of two modifications of (1R,3S)-dimethyl 2-oxocyclohexane-1,3-dicarboxylate were solved simultaneously from a single crystal using X-ray diffraction.

Online 13 September 2013


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Acta Cryst. (2013). B69, 514-523  [ doi:10.1107/S2052519213020277 ]

Hydrogen-bond landscapes, geometry and energetics of squaric acid and its mono- and dianions: a Cambridge Structural Database, IsoStar and computational study

F. H. Allen, A. J. Cruz-Cabeza, P. A. Wood and D. A. Bardwell

Synopsis: Hydrogen bonds involving squaric acid and its monoanion are similar in length and strength to those made by carboxylic acid donors and carboxylate COO- acceptors, while hydrogen bonds accepted by the squarate dianion are somewhat stronger. The mono- and dianions have been added as new central groups to the Cambridge Crystallographic Data Centre's (CCDC) IsoStar knowledge base of intermolecular interactions.

Online 13 September 2013


book reviews


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Acta Cryst. (2013). B69, 524-526  [ doi:10.1107/S2052519213018708 ]

Symmetry Relationships between Crystal Structures

Online 19 September 2013


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