Acta Crystallographica Section B

Structural Science, Crystal Engineering and Materials

Volume 69, Part 1 (February 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].

lead articles


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Acta Cryst. (2013). B69, 1-16  [ doi:10.1107/S2052519212051366 ]

The charge-flipping algorithm in crystallography

L. Palatinus

Synopsis: The state-of-the-art charge-flipping algorithm is summarized, and its applications to various crystallographic problems connected with structure solution are reviewed.

Online 19 January 2013


research papers


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Acta Cryst. (2013). B69, 17-29  [ doi:10.1107/S205251921205110X ]

The role of the coordination defect (CD) in the structures of anion-deficient, fluorite-related compounds

D. J. M. Bevan, L. L. Martin and R. L. Martin

Synopsis: The many superstructure phases of rare-earth oxides MnO2n - 2 are rationalized in terms of the `coordination defect model'.

Online 19 January 2013


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Acta Cryst. (2013). B69, 30-35  [ doi:10.1107/S2052519213000183 ]

Structural transformations in the low-temperature grown GaAs with superlattices of Sb and P [delta]-layers

M. V. Baidakova, N. A. Bert, V. V. Chaldyshev, V. N. Nevedomsky, M. A. Yagovkina, V. V. Preobrazhenskii, M. A. Putyato and B. R. Semyagin

Synopsis: Structural transformations in superlattices of Sb and P [delta]-layers upon annealing were studied in low-temperature grown GaAs. The combination of Sb and P [delta]-layers appears to be an effective tool for spatial patterning of arsenic nanoinclusions and prevention of the defect formation in the GaAs matrix.

Online 19 January 2013


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Acta Cryst. (2013). B69, 36-42  [ doi:10.1107/S2052519212046738 ]

Electronic influence of [beta]-diketonato-type ligands on the coordination of 1,5-cyclooctadiene to palladium(II) as defined by `Venus fly trap' geometric parameters

T. N. Hill, A. Roodt and G. Steyl

Synopsis: The influence of inter- and intramolecular interactions in a range of palladium(II) [beta]-diketonato complexes, as investigated by single-crystal X-ray crystallography, is presented in relation to solid-state packing modes, bond distances, hydrogen bonds and halogen interactions, while the `Venus fly trap' parameters of the 1,5-cyclooctadiene ligand are defined as a function of its bonding to the palladium(II) metal centre.

Online 20 December 2012


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Acta Cryst. (2013). B69, 43-54  [ doi:10.1107/S2052519212050439 ]

Weak intermolecular hydrogen and halogen interactions in an isomorphous halogen series of pseudoterpyridine ZnII complexes

F. Dumitru, Y.-M. Legrand, M. Barboiu and A. van der Lee

Synopsis: The structures of four halogen pseudoterpyridine ZnII complexes are analysed for the influence of very weak intermolecular interactions on their crystal packings.

Online 19 January 2013


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Acta Cryst. (2013). B69, 55-61  [ doi:10.1107/S2052519212048336 ]

Structural and electronic aspects of hydrogen bonding in two polymorphs of butylene-N,N'-bis(O,O'-diarylphosphoramidate)

K. Gholivand, A. A. E. Valmoozi and H. R. Mahzouni

Synopsis: The solid-state and gas-phase structure of (C6H5O)2P(O)NH(CH2)4NHP(O)(OC6H5)2 are reported.

Online 20 December 2012


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Acta Cryst. (2013). B69, 62-69  [ doi:10.1107/S2052519212047410 ]

Entry point into new trimeric and tetrameric imide-based macrocyclic esters derived from isophthaloyl dichloride and methyl 6-aminonicotinate

P. Mocilac and J. F. Gallagher

Synopsis: The reaction of isophthaloyl dichloride with methyl 6-aminonicotinate yields `3 + 3' and `4 + 4' imide-linked macrocycles with the former representing a new macrocycle class (trezimide). The role of 2-aminopyridine in imide hinge formation and ultimately macrocyclization is pivotal to this one-step synthetic route into cyclic triimides (trezimides) and tetraimides (tennimides).

Online 20 December 2012


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Acta Cryst. (2013). B69, 70-76  [ doi:10.1107/S2052519212049329 ]

Thermodynamic and structural relationships between the two polymorphs of 1,3-dimethylurea

C. Näther, C. Döring, I. Jess, P. G. Jones and C. Taouss

Synopsis: Polymorph (I) of dimethylurea (Fdd2) is the more stable modification at room temperature, where polymorph (II) (P21212) is metastable; the thermodynamic transition temperature lies between 253 K and room temperature.

Online 20 December 2012


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Acta Cryst. (2013). B69, 77-85  [ doi:10.1107/S2052519212051147 ]

A high-pressure polymorph of chlorpropamide formed on hydrostatic compression of the [alpha]-form in saturated ethanol solution

Y. V. Seryotkin, T. N. Drebushchak and E. V. Boldyreva

Synopsis: The crystal structure of a high-pressure monoclinic polymorph (P2111) of chlorpropamide has been determined. It is formed at ~ 2.8 GPa on hydrostatic compression of the orthorhombic stable [alpha]-polymorph (P212121) in saturated ethanol solution.

Online 19 January 2013


short communications


 

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Acta Cryst. (2013). B69, 86-89  [ doi:10.1107/S2052519212051500 ]

On the shortest BIII-O bonds

V. Sidey

Synopsis: For the crystal structures of oxoborates, the value of ~ 1.2 Å can be regarded as the lower physical limit for BIII-O bond lengths. The oxoborate crystal structures with BIII-O bond lengths shorter than ~ 1.2 Å have been found to be either doubtful or clearly erroneous.

Online 19 January 2013


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