This page contains a selection of articles from Crystallography Journals Online that have been highlighted in the IUCr newsletter.
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  Acta Cryst. (2007). A63, 465-480 [ doi:10.1107/S0108767307047411 ] The crystallographic fast Fourier transform. Recursive symmetry reductionA. Kudlicki, M. Rowicka and Z. OtwinowskiWe present algorithms for non-redundant crystallographic fast Fourier transform (FFT), maximally reducing the computational complexity and memory usage for all 230 symmetry groups. Previously such algorithms have been known only in several cases. The central idea of our approach is to represent a symmetric Fourier transform as a series of transforms on grids with no special points. Such transforms are reduced to P1 FFTs in one step. We provide recipes for recursive decomposition for all symmetry groups and grids. |  The fractal-like asymmetric unit for diagonal mirror symmetry. Color saturation depicts depth of recursion. | |
     Acta Cryst. (2007). B63, 926-932 [ doi:10.1107/S0108768107050823 ] Rietveld refinement of a wrong crystal structureC. Buchsbaum and M. U. SchmidtRietveld refinements are used to confirm crystal structures solved from powder diffraction data. The Rietveld refinement of the X-ray powder pattern of -quinacridone with the crystal structure of  -quinacridone gives a good fit, and a reasonable looking crystal structure. However, the lattice parameters, molecular conformation and packing are wrong. This example shows that a successful Rietveld refinement is not always final proof of the correctness of a crystal structure. |  Molecular formula of quinacridone and powder diagram of the phase. | |
      Acta Cryst. (2007). C63, o613-o616 [ doi:10.1107/S0108270107045465 ] Two modifications of a five-coordinate silicon complexU. Böhme and I. C. FoehnFormula: C14H19NO2Si The existence of polymorphs is of importance for many applications that depend on the solid state properties of a compound. TBPY-5-34-(Butane-1,4-diyl)(2-{[1-(2-oxidophenyl)ethylidene- O]amino-N}ethanolato-O)silicon, C14H19NO2Si, crystallizes in two modifications. The monoclinic form, (IIm), was obtained by crystallization over a period of 2 days at room temperature; the orthorhombic form, (IIo), crystallized overnight at 248 K. According to thermal analysis it was concluded that (IIm) is the thermodynamically stable modification and (IIo) is a kinetically formed modification. |  | |
  Acta Cryst. (2007). D63, 1069-1074 [ doi:10.1107/S0907444907042230 ] Structure determination of the O-methyltransferase NovP using the `free lunch algorithm' as implemented in SHELXEI. Usón, C. E. M. Stevenson, D. M. Lawson and G. M. SheldrickIn an ideal world, all macromolecules should diffract to atomic resolution. Sadly, this is hardly ever the case. For the title protein native data to 1.35 Å resolution and a single mercury derivative to 2.45 Å did not yield an interpretable map with the available programs in the hands of the authors. It could only be solved after using main-chain tracing and data extrapolation to fill in missing reflections to extend data to 1 Å — the ‘free lunch algorithm’ — as implemented in the program SHELXE. |  SIRAS combined with partial tracing and free lunch to 1 Å. | |
       Acta Cryst. (2007). E63, o4393 [ doi:10.1107/S1600536807050945 ] 2,8-Dimethoxy-4,10-dimethyl-1,3,7,9-tetranitro-6H,12H-5,11-methanodibenzo[b,f][1,5]diazocineM. D. H. Bhuiyan, P. Jensen and A. C. TryTrögerŐs base is a chiral, C2-symmetric compound with a V-shaped geometry. Analogues of the compound are of interest in areas such as molecular recognition and asymmetric catalysis; however, applications have been limited by the type of substituents (generally electron-donating) that could be incorporated on the aryl rings. In this study the structure determination of a tetranitro analogue is reported, in which the dihedral angle between the two aromatic rings is 103.64 (5)°. The crystal chosen for analysis crystallised in enantiopure form from a racemic mixture. |  | |
  Acta Cryst. (2007). F63, 831-835 [ doi:10.1107/S1744309107042455 ] Structure of Mycobacterium tuberculosis mtFabD, a malonyl-CoA:acyl carrier protein transacylase (MCAT)H. Ghadbane, A. K. Brown, L. Kremer, G. S. Besra and K. FüttererMycolic acids — very long -alkyl, -hydroxylated fatty acids — are essential and characteristic components of the cell envelope of Mycobacterium tuberculosis, and are synthesised by the joint action of the type I and II fatty acid synthase (FAS) systems. The 3.0 Å crystal structure of M. tuberculosis FabD, which catalyses acyl transfer from coenzyme A to acyl carrier protein of FAS-II, was phased based on anomalous scattering of five ordered Ni2+ ions bound to the His6-affinity tag of the recombinant enzyme. |  | |
   J. Appl. Cryst. (2007). 40, 1183-1188 [ doi:10.1107/S0021889807048777 ] ARPGE: a computer program to automatically reconstruct the parent grains from electron backscatter diffraction dataC. CayronA computer program called ARPGE automatically reconstructs the parent grains from EBSD data obtained on phase transition materials, with or without residual parent phase. The misorientations between the daughter grains are identified with operators, the daughter grains are identified with indexed variants, the orientations of the parent grains are determined and some statistics on the variants and operators can be established. Some examples with martensitic transformations in steels and titanium alloys have been treated. Variant selection phenomena have been revealed. |  Bainitic steel with the reconstruction of the austenitic grains. | |
  J. Synchrotron Rad. (2007). 14, 453-470 [ doi:10.1107/S0909049507037600 ] Coherent X-ray scattering and lensless imaging at the European XFEL FacilityI. A. Vartanyants, I. K. Robinson, I. McNulty, C. David, P. Wochner and Th. TschentscherCoherent X-ray diffraction imaging (CXDI) is a rapidly advancing form of lensless microscopy. The phase information of the diffraction pattern is embedded in a sufficiently sampled coherent diffraction pattern. Applying advanced computational methods based on iterative algorithms this diffraction pattern can be inverted to produce an image of a sample with diffraction-limited resolution. It is natural and highly attractive to use fully coherent X-ray beams produced by X-ray free-electron lasers (XFELs) for imaging nanoscale materials, magnetic domains and biological samples. In this article the scientific case, requirements and the possible realization of the coherent X-ray diffraction imaging experiments at the European XFEL Facility are discussed in detail. |  An artistic view of the experimental hall of the European XFEL and laboratory complex as viewed from the incoming photon tunnels. | |
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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. ![[eta]](/logos/entities/eta_rmgif.gif)
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. ![[rightwards arrow]](/logos/entities/rarr_rmgif.gif)
Arg surface mutations on the crystallization of the globular domain of RhoGDI. Acta Cryst. D60, 275-280. ![[nu]](/logos/entities/nu_rmgif.gif)
-AlCrFe phase by electron crystallography. Acta Cryst. A59, 526-539.