Twinning in 5-fluorosalicylic acid: description of a new polymorph

2018 ◽  
Vol 74 (1) ◽  
pp. 1-6
Author(s):  
Martin Lutz ◽  
Jara F. Vliem ◽  
Hendrik P. Rodenburg
Keyword(s):  
Crystal Structure ◽  
Unit Cell ◽  
Monoclinic Crystal System ◽  
Asymmetric Unit ◽  
Group Setting ◽  
Unit Cell Parameters ◽  
Monoclinic Crystal ◽  
Acta Cryst ◽  
Cell Parameters ◽  
Crystal System

The crystal structure of 5-fluorosalicylic acid is known from the literature [Choudhury & Guru Row (2004). Acta Cryst. E60, o1595–o1597] as crystallizing in the monoclinic crystal system with space-group setting P21/n and with one molecule in the asymmetric unit (polymorph I). We describe here a new polymorph which is again monoclinic but with different unit-cell parameters (polymorph II). Polymorph II has two molecules in the asymmetric unit. Its structure was modelled as a twin, with a pseudo-orthorhombic C-centred twin cell.

scholarly journals Synthesis, Characterization, and Crystal Structure of Negundoside (2′-p-Hydroxybenzoyl Mussaenosidic Acid)

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Suresh Sharma ◽  
B. D. Gupta ◽  
Rajni Kant ◽  
Vivek K. Gupta
Keyword(s):  
Crystal Structure ◽  
Room Temperature ◽  
Direct Method ◽  
Monoclinic Crystal System ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
Monoclinic Crystal ◽  
Full Matrix ◽  
X Ray ◽  
Cell Parameters

The structure of title compound Negundoside (2′-p-hydroxybenzoyl mussaenosidic acid) was established by spectral and X-ray diffraction studies. The compound crystallizes in the monoclinic crystal system with space group P21 having unit cell parameters: a=11.6201 (5) Å, b=9.2500 (4) Å, c=12.2516 (5) Å, β=97.793 (4)°, and Z=2. The crystal structure was solved by direct method using single crystal X-ray diffraction data collected at room temperature and refined by full-matrix least-squares procedures to a final R value of 0.0520 for 3389 observed reflections.

scholarly journals Crystal Structure Refinements of Four Monazite Samples from Different Localities

Minerals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1028 ◽  
Author(s):  
M. Mashrur Zaman ◽  
Sytle M. Antao
Keyword(s):  
Crystal Structure ◽  
Electron Probe ◽  
Unit Cell Volume ◽  
Unit Cell ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters ◽  
Large Unit Cell ◽  
A Site

This study investigates the crystal chemistry of monazite (APO4, where A = Lanthanides = Ln, as well as Y, Th, U, Ca, and Pb) based on four samples from different localities using single-crystal X-ray diffraction and electron-probe microanalysis. The crystal structure of all four samples are well refined, as indicated by their refinement statistics. Relatively large unit-cell parameters (a = 6.7640(5), b = 6.9850(4), c = 6.4500(3) Å, β = 103.584(2)°, and V = 296.22(3) Å3) are obtained for a detrital monazite-Ce from Cox’s Bazar, Bangladesh. Sm-rich monazite from Gunnison County, Colorado, USA, has smaller unit-cell parameters (a = 6.7010(4), b = 6.9080(4), c = 6.4300(4) Å, β = 103.817(3)°, and V = 289.04(3) Å3). The a, b, and c unit-cell parameters vary linearly with the unit-cell volume, V. The change in the a parameter is large (0.2 Å) and is related to the type of cations occupying the A site. The average <A-O> distances vary linearly with V, whereas the average <P-O> distances are nearly constant because the PO4 group is a rigid tetrahedron.

scholarly journals Crystallization and X-ray diffraction analysis of native and selenomethionine-substituted PhyH-DI fromBacillussp. HJB17

2017 ◽  
Vol 73 (11) ◽  
pp. 607-611
Author(s):  
Fang Lu ◽  
Bei Zhang ◽  
Yong Liu ◽  
Ying Song ◽  
Gangxing Guo ◽  
...  
Keyword(s):  
Unit Cell ◽  
Diffusion Method ◽  
Data Sets ◽  
Asymmetric Unit ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
Solvent Content ◽  
Space Group ◽  
X Ray ◽  
Cell Parameters

Phytases are phosphatases that hydrolyze phytates to less phosphorylatedmyo-inositol derivatives and inorganic phosphate. β-Propeller phytases, which are very diverse phytases with improved thermostability that are active at neutral and alkaline pH and have absolute substrate specificity, are ideal substitutes for other commercial phytases. PhyH-DI, a β-propeller phytase fromBacillussp. HJB17, was found to act synergistically with other single-domain phytases and can increase their efficiency in the hydrolysis of phytate. Crystals of native and selenomethionine-substituted PhyH-DI were obtained using the vapour-diffusion method in a condition consisting of 0.2 Msodium chloride, 0.1 MTris pH 8.5, 25%(w/v) PEG 3350 at 289 K. X-ray diffraction data were collected to 3.00 and 2.70 Å resolution, respectively, at 100 K. Native PhyH-DI crystals belonged to space groupC121, with unit-cell parametersa = 156.84,b = 45.54,c = 97.64 Å, α = 90.00, β = 125.86, γ = 90.00°. The asymmetric unit contained two molecules of PhyH-DI, with a corresponding Matthews coefficient of 2.17 Å3 Da−1and a solvent content of 43.26%. Crystals of selenomethionine-substituted PhyH-DI belonged to space groupC2221, with unit-cell parametersa = 94.71,b= 97.03,c= 69.16 Å, α = β = γ = 90.00°. The asymmetric unit contained one molecule of the protein, with a corresponding Matthews coefficient of 2.44 Å3 Da−1and a solvent content of 49.64%. Initial phases for PhyH-DI were obtained from SeMet SAD data sets. These data will be useful for further studies of the structure–function relationship of PhyH-DI.

X-ray analysis of crystals of rat phosphatidylinositol-transfer protein with bound phosphatidylcholine

1999 ◽  
Vol 55 (2) ◽  
pp. 522-524 ◽  
Author(s):  
Randall L. Oliver ◽  
Jacqueline M. Tremblay ◽  
George M. Helmkamp ◽  
Lynwood R. Yarbrough ◽  
Natalie W. Breakfield ◽  
...  
Keyword(s):  
Crystal Form ◽  
Unit Cell ◽  
Asymmetric Unit ◽  
Unit Cell Parameters ◽  
Vapor Diffusion ◽  
Solvent Content ◽  
Cell Parameters ◽  
Transfer Protein ◽  
Phosphatidylinositol Transfer Protein ◽  
Phosphatidylinositol Transfer

Phosphatidylinositol-transfer protein (PITP) is a soluble, ubiquitously expressed, highly conserved protein encoded by two genes in humans, rodents and other mammals. A cDNA encoding the alpha isoform of the rat gene was expressed to high levels in Escherichia coli, the protein purified and the homogeneous protein used for crystallization studies. Crystals of rat PITP-α were obtained by vapor-diffusion techniques using the sitting-drop method. Crystals grow within two weeks by vapor-diffusion techniques in the presence of polyethylene glycol 4000. Both crystal forms pack in the monoclinic space group P21. Crystal form I has unit-cell parameters a = 44.75, b = 74.25, c = 48.32 Å and β = 114.14°. Unit-cell parameters for crystal form II are a = 47.86, b = 73.59, c = 80.49 Å and β = 98.54°. Crystal form I has a Vm of 2.295 Å3 Da−1 and an estimated solvent content of 46.4% with one molecule per asymmetric unit, while crystal form II has a Vm of 2.196 Å3 Da−1 and an estimated solvent content of 44.0%, assuming two molecules per asymmetric unit.

scholarly journals The crystal structure of alstonite, BaCa(CO3)2: an extraordinary example of ‘hidden’ complex twinning in large single crystals

2020 ◽  
Vol 84 (5) ◽  
pp. 699-704
Author(s):  
Luca Bindi ◽  
Andrew C. Roberts ◽  
Cristian Biagioni
Keyword(s):  
Crystal Structure ◽  
Single Crystals ◽  
Structure Determination ◽  
Unit Cell ◽  
Crystal Structure Determination ◽  
Unit Cell Parameters ◽  
Space Group ◽  
Cell Parameters ◽  
Structure Determinations

AbstractAlstonite, BaCa(CO3)2, is a mineral described almost two centuries ago. It is widespread in Nature and forms magnificent cm-sized crystals. Notwithstanding, its crystal structure was still unknown. Here, we report the crystal-structure determination of the mineral and discuss it in relationship to other polymorphs of BaCa(CO3)2. Alstonite is trigonal, space group P31m, with unit-cell parameters a = 17.4360(6), c = 6.1295(2) Å, V = 1613.80(9) Å3 and Z = 12. The crystal structure was solved and refined to R1 = 0.0727 on the basis of 4515 reflections with Fo > 4σ(Fo) and 195 refined parameters. Alstonite is formed by the alternation, along c, of Ba-dominant and Ca-dominant layers, separated by CO3 groups parallel to {0001}. The main take-home message is to show that not all structure determinations of minerals/compounds can be solved routinely. Some crystals, even large ones displaying excellent diffraction quality, can be twinned in complex ways, thus making their study a crystallographic challenge.

scholarly journals Crystal Chemistry and High-Temperature Behaviour of Ammonium Phases NH4MgCl3·6H2O and (NH4)2Fe3+Cl5·H2O from the Burned Dumps of the Chelyabinsk Coal Basin

Minerals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 486 ◽  
Author(s):  
Andrey A. Zolotarev ◽  
Elena S. Zhitova ◽  
Maria G. Krzhizhanovskaya ◽  
Mikhail A. Rassomakhin ◽  
Vladimir V. Shilovskikh ◽  
...  
Keyword(s):  
Crystal Structure ◽  
High Temperature ◽  
Unit Cell ◽  
X Ray Diffraction ◽  
Coal Basin ◽  
Unit Cell Parameters ◽  
Space Group ◽  
X Ray ◽  
Cell Parameters ◽  
Mineral Phases

The technogenic mineral phases NH4MgCl3·6H2O and (NH4)2Fe3+Cl5·H2O from the burned dumps of the Chelyabinsk coal basin have been investigated by single-crystal X-ray diffraction, scanning electron microscopy and high-temperature powder X-ray diffraction. The NH4MgCl3·6H2O phase is monoclinic, space group C2/c, unit cell parameters a = 9.3091(9), b = 9.5353(7), c = 13.2941(12) Å, β = 90.089(8)° and V = 1180.05(18) Å3. The crystal structure of NH4MgCl3·6H2O was refined to R1 = 0.078 (wR2 = 0.185) on the basis of 1678 unique reflections. The (NH4)2Fe3+Cl5·H2O phase is orthorhombic, space group Pnma, unit cell parameters a = 13.725(2), b = 9.9365(16), c = 7.0370(11) Å and V = 959.7(3) Å3. The crystal structure of (NH4)2Fe3+Cl5·H2O was refined to R1 = 0.023 (wR2 = 0.066) on the basis of 2256 unique reflections. NH4MgCl3·6H2O is stable up to 90 °C and then transforms to the less hydrated phase isotypic to β-Rb(MnCl3)(H2O)2 (i.e., NH4MgCl3·2H2O), the latter phase being stable up to 150 °C. (NH4)2Fe3+Cl5·H2O is stable up to 120 °C and then transforms to an X-ray amorphous phase. Hydrogen bonds provide an important linkage between the main structural units and play the key role in determining structural stability and physical properties of the studied phases. The mineral phases NH4MgCl3·6H2O and (NH4)2Fe3+Cl5·H2O are isostructural with natural minerals novograblenovite and kremersite, respectively.

scholarly journals Structural characterization of a novel monotreme-specific protein with antimicrobial activity from the milk of the platypus

2018 ◽  
Vol 74 (1) ◽  
pp. 39-45 ◽  
Author(s):  
Janet Newman ◽  
Julie A. Sharp ◽  
Ashwantha Kumar Enjapoori ◽  
John Bentley ◽  
Kevin R. Nicholas ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Antimicrobial Activity ◽  
Mammalian Cells ◽  
Unit Cell ◽  
Protein Crystal ◽  
Unit Cell Parameters ◽  
Flag Epitope ◽  
Data Set ◽  
Space Group ◽  
Cell Parameters

Monotreme lactation protein (MLP) is a recently identified protein with antimicrobial activity. It is present in the milk of monotremes and is unique to this lineage. To characterize MLP and to gain insight into the potential role of this protein in the evolution of lactation, the crystal structure of duck-billed platypus (Ornithorhynchus anatinus) MLP was determined at 1.82 Å resolution. This is the first structure to be reported for this novel, mammalian antibacterial protein. MLP was expressed as a FLAG epitope-tagged protein in mammalian cells and crystallized readily, with at least three space groups being observed (P1,C2 andP21). A 1.82 Å resolution native data set was collected from a crystal in space groupP1, with unit-cell parametersa= 51.2,b= 59.7,c= 63.1 Å, α = 80.15, β = 82.98, γ = 89.27°. The structure was solved by SAD phasing using a protein crystal derivatized with mercury in space groupC2, with unit-cell parametersa= 92.7,b = 73.2,c= 56.5 Å, β = 90.28°. MLP comprises a monomer of 12 helices and two short β-strands, with much of the N-terminus composed of loop regions. The crystal structure of MLP reveals no three-dimensional similarity to any known structures and reveals a heretofore unseen fold, supporting the idea that monotremes may be a rich source for the identification of novel proteins. It is hypothesized that MLP in monotreme milk has evolved to specifically support the unusual lactation strategy of this lineage and may have played a central role in the evolution of these mammals.

scholarly journals Crystallization and preliminary X-ray analysis of human rhinovirus serotype 2 (HRV2)

1999 ◽  
Vol 55 (8) ◽  
pp. 1459-1461 ◽  
Author(s):  
Núria Verdaguer ◽  
Thomas C. Marlovits ◽  
Jerónimo Bravo ◽  
David I. Stuart ◽  
Dieter Blaas ◽  
...  
Keyword(s):  
Potassium Phosphate ◽  
Attachment Site ◽  
Unit Cell ◽  
Human Rhinovirus ◽  
Intercellular Adhesion Molecule ◽  
Upper Respiratory Tract ◽  
Asymmetric Unit ◽  
Unit Cell Parameters ◽  
Space Group ◽  
Cell Parameters

Human rhinoviruses, the major cause of mild recurrent infections of the upper respiratory tract, are small icosahedral particles. Over 100 different serotypes have been identified. The majority (91 serotypes) use intercellular adhesion molecule 1 as the cell-attachment site; ten serotypes (the minor group) bind to members of the low-density lipoprotein receptor. Three different crystal forms of the minor-group human rhinovirus serotype 2 (HRV2) were obtained by the hanging-drop vapour-diffusion technique using ammonium sulfate and sodium/potassium phosphate as precipitants. Monoclinic crystals, space group P21, diffracted at least to 2.8 Å resolution, and two complete virus particles were located in the crystal asymmetric unit. A second type of crystals had a compact cubic like morphology and diffracted beyond 2.5 Å resolution. These crystals belong to a primitive orthorhombic space group, with unit-cell parameters a = 309.3, b = 353.5, c = 759.6 Å, and contain one virus particle in the asymmetric unit. A third type of crystals, with a prismatic shape and belonging to space group I222, was also obtained under similar crystallization conditions. These latter crystals, with unit-cell parameters a = 308.7, b = 352.2, c = 380.5 Å, diffracted to high resolution (beyond 1.8 Å) and contained 15 protomers per asymmetric unit; this requires that three perpendicular crystal twofold axes coincide with three of the viral particle's dyad axes.

Crystal structure of three diaza-crowns-18

1997 ◽  
Vol 212 (5) ◽  
Author(s):  
P. Dokurno ◽  
R. Trokowski ◽  
B. Kościuszko-Panek ◽  
T. Ossowski ◽  
A. Konitz ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Crystal Structures ◽  
Unit Cell ◽  
Unit Cell Parameters ◽  
Space Groups ◽  
Cell Parameters

AbstractThe crystal structures of three diaza crowns-18, namely 1,4,10,13-tetraoxa-7,16-diazacyclooctadecane (crown 1), 1,4,10,13-tetraoxa-7,16-diazacyclooctadecane-7,16-diacetonitrile (crown 2) and N,N′-(1,4,10,13-tetraoxa-7,16-diazacyclooctadecane-7,16-diyldi-2,1-ethanediyl)bis-[4-methyl-benzenesulfonamide] (crown 3) have the following space groups and unit cell parameters: crown 1(C

X-ray-diffraction data of Pb2(C2O4)(NO3)2·2H2O

1996 ◽  
Vol 11 (1) ◽  
pp. 7-8 ◽  
Author(s):  
Hee-Lack Choi ◽  
Nobuo Ishizawa ◽  
Naoya Enomoto ◽  
Zenbe-e Nakagawa
Keyword(s):  
Powder Diffraction ◽  
Diffraction Data ◽  
Unit Cell ◽  
Powder Diffraction Data ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters ◽  
Crystal System

X-ray powder-diffraction data for Pb2(C2O4)(NO3)2·2H2O were obtained. The crystal system was determined to be monoclinic. The unit-cell parameters were refined to a=10.613(2) Å, b=7.947(2) Å, c=6.189(1) Å, and β=104.48(2)°.

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