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Acta Cryst. (2009). A65, 300-311 [ doi:10.1107/S0108767309019862 ] Towards the best model for H atoms in experimental charge-density refinementA. A. Hoser, P. M. Dominiak and K. WozniakWithout neutron data, a mixed X-ray multipole refinement (high-order refinement of heavy atoms, low-angle refinement of H atoms and elongation of X–H distances to the average neutron values) supplemented by estimation of anisotropic thermal motion of H atoms gives the best topological and integrated properties of experimental . Topological parameters calculated by using different models of H atoms should not be compared. Standardization of X–H distances to the average neutron data without any additional improvements of ADPs and X–H directions will not supply the correct topological parameters. | ![]() | |
Acta Cryst. (2009). B65, 249-268 [ doi:10.1107/S0108768109015614 ] A non-mathematical introduction to the superspace description of modulated structuresT. Wagner and A. SchönleberDiffraction patterns of modulated structures cannot be indexed with three integer numbers. The necessity to use four or more indices instead must be understood as a loss of translational symmetry in three dimensions. To restore this periodicity the concept of higher-dimensional space was developed during the second half of the last century. In this paper it is introduced in a strictly non-mathematical way, and the complete structure determination process within this so-called superspace approach is illustrated using the incommensurately modulated crystal structure of a typical organic compound, C19H27NO3Si. | ![]() Missing translational symmetry in the modulated crystal structure of C19H27NO3Si. | |
Acta Cryst. (2009). C65, o388-o395 [ doi:10.1107/S0108270109025141 ] Enantiotropic phase transition and twinning in 2,2,3,3,4,4-hexafluoropentane-1,5-diolJ.-M. Ha and V. YoungFormula: Four forms of C5H6F6O2 The organic compound 2,2,3,3,4,4-hexafluoropentane-1,5-diol (HFPD) was found to undergo a temperature-dependent phase transition between two closely related triclinic polymorphs. Each of the two phases is twinned with either two or four individuals depending on the temperature cycling history. The molecules form sheets that slide with respect to others during the phase transition. The phase transition is triggered by the natural contraction of the unit cell upon cooling coupled with several unfavorable C–H...F and F...F non-bonded contacts. | ![]() The superposition of (012) layers of two forms is presented to illustrate sliding of the layers during the enantiotropic phase transition of HFPD. | |
Acta Cryst. (2009). D65, 906-912 [ doi:10.1107/S0907444909020927 ] Rotational order-disorder structure of fluorescent protein FP480S. Pletnev, K. S. Morozova, V. V. Verkhusha and Z. DauterActa Cryst. (2009). D65, 966-973 [ doi:10.1107/S0907444909023695 ] Application of general formulas for the correction of a lattice-translocation defect in crystals of a lentiviral integrase in complex with LEDGFS. Hare, P. Cherepanov and J. WangActa Cryst. (2009). D65, 980-988 [ doi:10.1107/S0907444909025153 ] Analysis of lattice-translocation disorder in the layered hexagonal structure of carboxysome shell protein CsoS1CY. Tsai, M. R. Sawaya and T. O. YeatesThree instances are reported of protein crystals exhibiting different kinds of order–disorder phenomena. These types of disorder are distinct from twinning, and might be unfamiliar to macromolecular crystallographers. Hare et al. and Tsai et al. both report crystals containing multiple distinct lattices related by discrete translation vectors, a situation referred to as lattice translocation disorder, while Pletnev et al. describe a different situation in which layers of molecules related by a 90° rotation appear stochastically throughout the crystal. Various treatments are discussed for handling this class of problems. | ||
Acta Cryst. (2009). E65, o1724 [ doi:10.1107/S1600536809024416 ] N3,N6,2,5,7-Pentaphenyl-2,5,7-triazabicyclo[2.2.1]heptane-3,6-diamineA. Taheri and S. M. MoosaviA derivative of triazanorbornane has been synthesized and is the first such compound to be fully characterized by X-ray crystallographic analysis. The six-membered diaza ring is in a chair conformation but the bridging aza atom produces ring strain. Despite this, the structure is completely stable due to anomeric interactions in the N–C–N groups. | ![]() Displacement ellipsoids drawn at 50% probability level. H atoms are omitted for a clearer view of the norbornane skeleton. | |
Acta Cryst. (2009). F65, 540-543 [ doi:10.1107/S1744309109014249 ] Structure of AmpC | ![]() Slabbed view of overall structure superposition of native AmpC -lactamase (red) (PDB code 1KE4) and AmpCD -lactamase (blue) (PDB code 2ZJ9). | |
J. Appl. Cryst. (2009). 42, 834-845 [ doi:10.1107/S0021889809023218 ] Experimental and theoretical study of the diffraction properties of various crystals for the realization of a soft gamma-ray Laue lensN. Barrière, J. Rousselle, P. von Ballmoos, N. V. Abrosimov, P. Courtois, P. Bastie, T. Camus, M. Jentschel, V. N. Kurlov, L. Natalucci, G. Roudil, N. Frisch Brejnholt and D. SerreCrystals are the elementary constituents of Laue lenses, an emerging technology of gamma-ray optics working in the 100 keV–1.5 MeV energy range. This paper addresses the current endeavour to the development of efficient crystals for a Laue lens. We have calculated the diffraction efficiency of 35 mosaic crystals (pure or two-component) and among them we present the experimental characterization of Cu and Au. Crystals having curved diffracting planes also enter the scope of this study with measurements of SiGe composition-gradient crystals. | ![]() The principle of a Laue lens: a large number of crystal tiles arranged in concentric rings diffract radiation coming from infinity towards a common focus. Depending on the radius of the rings and the d-spacings of the crystals, the energy diffracted by the rings can be the same or overlap to cover a large energy band. | |
J. Synchrotron Rad. (2009). 16, 562-572 [ doi:10.1107/S0909049509017920 ] Advanced phase-contrast imaging using a grating interferometerS. A. McDonald, F. Marone, C. Hintermüller, G. Mikuljan, C. David, F. Pfeiffer and M. StampanoniFor the same dose imparted to the sample, X-ray phase contrast imaging provides increased contrast and sensitivity compared to conventional absorption based methods. At TOMCAT, the tomographic microscopy beamline of the Swiss Light Source, we implemented a phase-sensitive imaging device based on grating interferometry. The novel instrument, optimized for fast data acquisition and post-processing, enables high-throughput studies of low absorbing materials. A case study (see Figure) focuses on the visualization of morphological structures in a rat brain. | ![]() (a) Phase-contrast tomographic reconstruction of a rat brain: the coronal slice has been taken at the level of the substantia nigra. (b) and its inset show a region of interest imaged at a pixel resolution of 3.5 microns. | |


3-allyl)4Cl2(OH)2(CO)8: the first cubane-type Mo2+ organometallic complex with
3-OH and
3-Cl bridges. Acta Cryst. C65, m168-m170. 

5-pentamethylcyclopentadienyl)cobalt(II). Acta Cryst. E65, m391. 















4N,N',N'',N'''}bis(trifluoromethanesulfanato-
O)copper(II). Acta Cryst. E64, m1435. 












-2 polymorphs of trans-mono-unsaturated triacylglycerols and related fully saturated triacylglycerols. Acta Cryst. B64, 240-248. 
'-2 polymorphs of trans-mono-unsaturated triacylglycerols and related saturated TAGs and their polymorphic stability. Acta Cryst. B64, 249-259. 









2-hydroxido-bis[dioxouranium(VI)]]-di-
2-2-pyridylacetato-
3O,N:O';
3O:O',N]. Acta Cryst. C64, m50-m52. 















3-1,1-dioxo-1,2-benzoisothiazole-3-thiolato-
3N:S3:S3)silver(I)]. Acta Cryst. C63, m395-m397. 

































2S,S')bismuth(III). Acta Cryst. E62, m2552-m2554. 






5-hydrogenphosphato-pentamolybdate(VI) tetrahydrate. Acta Cryst. C62, m355-m357. 





-GaPO4. Acta Cryst. A62, 1-10. 

















-tetraethoxyborato]. Acta Cryst. C61, m417-m418. 










5-cyclopentadienyl)tungstenio]indium. Acta Cryst. E61, m945-m946. 





-acetato-acetonitriletris(
-N,N'-diphenylformamidinato)diruthenium tetrafluoroborate dichloromethane hemisolvate. Acta Cryst. C61, m71-m73. 















-chloro-bis[dichloropalladium(II)]. Acta Cryst. C60, m426-m430. 

-Diphenylphosphido-
-hydrido-bis[carbonyl(
5-cyclopentadienyl)iron(II)]. Acta Cryst. E60, m1284-m1285. 









-ray and neutron diffraction studies of CoF2: magnetostriction, electron density and magnetic moments. Acta Cryst. A60, 51-57. 


Arg surface mutations on the crystallization of the globular domain of RhoGDI. Acta Cryst. D60, 275-280. 



-AlCrFe phase by electron crystallography. Acta Cryst. A59, 526-539. 




























O)zinc(II). Acta Cryst. C59, m18-m20. 

-
-Stacking and nitro-
-stacking interactions of 1-(4-nitrophenyl)-4-phenyl-2,4-bis(phenylethynyl)butadiene. Acta Cryst. E59, o227-o229. 


-sheet structure formed by C-H
O hydrogen bonds between the thiazole rings and amide bonds of a dimeric desoxazoline ascidiacyclamide analogue. Acta Cryst. E57, o834-o838. 









C-terminal SH2-peptide complex. Acta Cryst. D57, 1397-1404. 





O hydrogen bond in urea-phosphoric acid (1/1). Acta Cryst. B57, 435-439. 



















-galactose and N-acetyllactosamine and a comparative study of carbohydrate binding in Gal/GalNAc-specific legume lectins. Acta Cryst. D55, 1375-1382. 











-oxo-bis[bis(bipyridine-N,N')manganese(III, IV)] Triperchlorate Bis(nitrobenzene) Hemihydrate. Acta Cryst. C54, 1797-1799. 






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