Crystal and molecular structures of the organometallic species [Rh2(bim)2(cod)2]Cl2∙2H2O [bim=bis-(1-imidazolyl)methane; cod=1, 5-cyclooctadiene]

2007 ◽  
Vol 22 (3) ◽  
pp. 236-240 ◽  
Author(s):  
Norberto Masciocchi ◽  
Alessandro Figini Albisetti ◽  
Angelo Sironi ◽  
Claudio Pettinari ◽  
Alessandro Marinelli
Keyword(s):  
Crystal Structure ◽  
Chloride Ions ◽  
Molecular Structures ◽  
Mirror Plane ◽  
Water Molecules ◽  
Powder Diffraction Data ◽  
X Ray ◽  
Crystal And Molecular Structures ◽  
Full Profile ◽  
Large Cation

The synthesis and X-ray powder diffraction data for the organometallic [Rh2(bim)2(cod)2]Cl2∙2H2O species are reported. Its crystal and molecular structures were determined by simulated annealing and full-profile Rietveld refinement methods. [Rh2(bim)2(cod)2]Cl2∙2H2O was found to crystallize in the orthorhombic Cmca space group. The lattice parameters were determined to be a=21.3574(6), b=10.7764(3), c=14.2795(4) Å, V=3286.5(2) Å3, for Z=4. The crystal structure was found to contain dimeric [Rh2(bim)2(cod)2]2+ cations, in which the bim ligands bridge Rh(cod) fragments with an intermetallic separation of ca. 8.90 Å. The crystal structure is completed by chloride ions and hydrogen-bonded water molecules, situated in the small cavities of the large cation substructure. The conformation of the bim ligand, lying on a crystallographic mirror plane, is rigorously Cs.

Synthesis and X-ray powder diffraction characterization of tetra- and hexa-imidazole complexes of magnesium(II)

2008 ◽  
Vol 23 (4) ◽  
pp. 286-291 ◽  
Author(s):  
Norberto Masciocchi ◽  
Luigi Garlaschelli ◽  
Giulia Peli
Keyword(s):  
Powder Diffraction ◽  
Molecular Structures ◽  
Water Molecules ◽  
Powder Diffraction Data ◽  
Monoclinic System ◽  
Space Group ◽  
X Ray ◽  
Imidazole Complexes ◽  
Full Profile

X-ray powder diffraction data for two ionic salts containing imidazole (Him) complexes of the magnesium(II) ion, [Mg(Him)4(H2O)2]Cl2 and [Mg(Him)6](NO3)2, are reported. Their crystal and molecular structures were determined by simulated annealing and full-profile Rietveld refinement methods. [Mg(Him)4(H2O)2]Cl2 was found to crystallize in the monoclinic system with space group C2/c, a=12.3980(3) Å, b=11.0234(2) Å, c=14.4691(3) Å, and β=107.024(1)°. [Mg(Him)6](NO3)2 crystallizes in the trigonal R-3 space group with a=b=12.4631(4) Å and c=14.9449(6) Å. Both species contain centrosymmetric complexes, and Mg is octahedrally coordinated by six imidazoles, as in [Mg(Him)6](NO3)2, or by four imidazoles and two water molecules, as in [Mg(Him)4(H2O)2]Cl2. Additional analytic, thermogravimetric, calorimetric, and spectroscopic characterizations were also performed.

Crystal structure and diffraction data for a polymorph of voglibose (C10H21NO7)

2010 ◽  
Vol 25 (S1) ◽  
pp. S28-S30
Author(s):  
G. Q. Zhang ◽  
G. L. Lv
Keyword(s):  
Crystal Structure ◽  
Simulated Annealing ◽  
Rigid Body ◽  
Rietveld Refinement ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Molecular Structures ◽  
Powder Diffraction Data ◽  
X Ray ◽  
Crystal And Molecular Structures

X-ray powder diffraction data of voglibose are reported, and its crystal and molecular structures were determined by simulated annealing and rigid-body Rietveld refinement methods. Voglibose was found to be crystallized in triclinic symmetry with space group P-1. The lattice parameters were determined to be a=6.1974(6) Å, b=6.9918(5) Å, c=7.3955(9) Å, α=70.8628(3), β=103.5312(4), γ=94.3867(5)°, V=294.2(2) Å3, and ρcal=1.495 g/cm3. The crystal structure contains isolated C10H21NO7 molecular.

Untersuchungen an Stickstoff-Brom-Verbindungen, IV / Studies on Nitrogen-Bromine Compounds, IV

1977 ◽  
Vol 32 (12) ◽  
pp. 1416-1420 ◽  
Author(s):  
Omar Jabay ◽  
Hans Pritzkow ◽  
Jochen Jander
Keyword(s):  
Crystal Structure ◽  
Nitrogen Atom ◽  
Structure Analysis ◽  
Electron Acceptors ◽  
Molecular Structures ◽  
Hydrogen Atoms ◽  
X Ray ◽  
Crystal And Molecular Structures ◽  
Solid Nitrogen ◽  
Intermolecular Contacts

The crystal and molecular structures of N-bromobenzamide (NBB), N-bromosuccinimide (NBS), and N,N-dibromobenzenesulfonamide (NBBS) were determined by X-ray structure analysis. The nitrogen atoms in NBB and NBS have a trigonal planar coordination (sp2) and the N—Br distances lie in the same range (1.82 A, 1.84 A). The N—Br distance in NBBS, where the nitrogen atom is sp3-hybridized, is somewhat longer (1.88 A). In these structures the molecules are connected by O···H—N (NBB), O···Br—N (NBS) or N···Br—N (NBBS) intermolecular bonds forming endless chains; positivated hydrogen atoms or, in case that they are absent, positivated bromine atoms act as electron acceptors with oxygen or sp3- hybridized nitrogen atoms. These results suggest, that in solid nitrogen tribromide, the crystal structure of which cannot be determined, the nitrogen atoms will be sp3-hybridized and intermolecular contacts via N—Br···N will occur.

Arsenic(III), Antimony (III) and Bismuth(III) Thiobenzoates: Crystal and Molecular Structures of M(SOCR)3 and PhSb(SOCPh)2

1998 ◽  
Vol 53 (12) ◽  
pp. 1475-1482 ◽  
Author(s):  
Prit Singh ◽  
Sudha Singh ◽  
Vishnu D. Gupta ◽  
Heinrich Nöth
Keyword(s):  
Crystal Structure ◽  
Molecular Structures ◽  
X Ray ◽  
Crystal And Molecular Structures ◽  
Covalently Bonded ◽  
Bismuth Complex ◽  
Group 15 ◽  
Structure Determinations ◽  
Trigonal Pyramid ◽  
Trigonal Prisms

Abstract Tris-thiobenzoates, Arsenic, Antimony, Bismuth Tris-thiobenzoates of arsenic, antimony and bismuth, M(SOCR)3 have been obtained from their oxides and characterized. In the X-ray crystal structure determinations of these, the group 15 atom and the three covalently bonded sulfur atoms are found to constitute a trigonal pyramid, the central atoms lie at a C3 axis. In the bismuth complex the thiobenzoate ligand tends to chelate. However, three comparatively short intermolecular M···S interactions are significant features for these molecules resulting in stacking of trigonal prisms providing an essentially six coordinate environment around arsenic and antimony and a nine-coordinate one for bismuth. The structure of PhSb(SOCPh)2 can be considered

Zýkait z dolu Lehnschafter u Mikulova v Krušných horách (Česká republika) - popis a Ramanova spektroskopie

2021 ◽  
Vol 29 (2) ◽  
pp. 241-248
Author(s):  
Jiří Sejkora ◽  
Roman Gramblička
Keyword(s):  
Crystal Structure ◽  
Raman Spectroscopy ◽  
Czech Republic ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Water Molecules ◽  
Powder Diffraction Data ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters

The zýkaite samples were found at abandoned Lehnschafter mine near Mikulov in the Krušné hory Mts. (Czech Republic). It occurs as irregular white to light greenish rounded to spherical aggregates up to 1.5 cm in size composed of tiny acicular crystals up to 5 - 10 μm in length. Its empirical formula can be expressed as (Fe3.79Al0.02)Σ3.81[(AsO4)2.66(PO4)0.20(SiO4)0.07]Σ2.93 (SO4)1.07(OH)0.44·15H2O (mean of 3 spot analyzes; on the basis of As+P+S+Si = 4 apfu).Zýkaite is probably monoclinic, with the unit-cell parameters refined from X-ray powder diffraction data: a 21.195(8), b 7.052(2), c 36.518(17) Å, β 91.07(2)° and V 5458(2) Å3. Raman spectroscopy documented the presence of both (AsO4)3- and (SO4)2- units in the crystal structure of zýkaite. Multiple Raman bands connected with vibrations of water molecules and (AsO4)3- groups indicate the presence of more structurally non-equivalent these groups in the crystal stucture of zýkaite.

Gobbinsite from Magheramorne Quarry, Northern Ireland

1994 ◽  
Vol 58 (393) ◽  
pp. 615-620 ◽  
Author(s):  
Gilberto Artioli ◽  
Harry Foy
Keyword(s):  
Crystal Structure ◽  
Northern Ireland ◽  
Crystal Chemistry ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Powder Diffraction Data ◽  
X Ray ◽  
Cell Parameters ◽  
Full Profile ◽  
Profile Technique

AbstractThe rare zeolite mineral gobbinsite has been found in vugs of altered basalts at the Magheramorne Quarry, Lane, Northern Ireland, intimately associated with phillipsite. The crystal chemistry of the sample (Na4.3Ca0.6Si10.4Al5.6O32·12H2O) is close to that reported for gobbinsite from the type locality. The crystal structure of the Magheramorne gobbinsite has been refined from X-ray powder diffraction data using the multiphase Rietveld full profile technique. The orthorhombic Pmn21 space group is confirmed. The refined cell parameters (a = 10.1027(5), b = 9.8016(5), and c = 10.1682(6) Å) are slightly different from those reported in the literature for the K-rich gobbinsite from Island Magee (a = 10.108(1), b = 9.766(1), and c = 10.171(1) Å), whose structure was also refined from powder data.

Crystal and molecular structures of 2-[1-(2-aminoethyl)-2-imidazolidinylidene]-2-nitroacetonitrile (C7H11N5O2) and 2,6-diamino-5-hydroxy-3-nitro-4H-pyrazolo[1,5-a]pyrimidin-7-one monohydrate (C6H6N6O4·H2O) from X-ray, synchrotron and neutron powder diffraction data

1999 ◽  
Vol 55 (4) ◽  
pp. 554-562 ◽  
Author(s):  
V. V. Chernyshev ◽  
A. N. Fitch ◽  
E. J. Sonneveld ◽  
A. I. Kurbakov ◽  
V. A. Makarov ◽  
...  
Keyword(s):  
Powder Diffraction ◽  
Diffraction Data ◽  
Neutron Powder Diffraction ◽  
Molecular Structures ◽  
Search Procedure ◽  
Grid Search ◽  
Powder Diffraction Data ◽  
X Ray ◽  
Crystal And Molecular Structures ◽  
Neutron Powder Diffraction Data

The crystal and molecular structures of 2-[1-(2-aminoethyl)-2-imidazolidinylidene]-2-nitroacetonitrile [C7H11N5O2; space group P21/n; Z = 4; a = 7.4889 (8), b = 17.273 (2), c = 7.4073 (8) Å, β = 111.937 (6)°], (I), and 2,6-diamino-5-hydroxy-3-nitro-4H-pyrazolo[1,5-a]pyrimidin-7-one monohydrate [C6H6N6O4·H2O; space group P21/n; Z = 4; a = 17.576 (3), b = 10.900 (2), c = 4.6738 (6) Å, β = 92.867 (8)°], (II), have been determined from X-ray, synchrotron and neutron powder diffraction data using various methods. The structures were originally solved from Guinier photographs with a grid search procedure and the program MRIA using a priori information from NMR and mass spectra on the possible geometry of the molecules. Because the conformation of molecule (I) changed during the bond-restrained Rietveld refinement, solvent water was found in (II) and, moreover, as both Guinier patterns were corrupted by texture, high-resolution texture-free synchrotron data were collected at the BM16 beamline, ESRF, to confirm the original results. Using the set of |F| 2 values derived from the synchrotron patterns after full-pattern decomposition procedures, the structures of (I) and (II) were solved by direct methods via SHELXS96, SIRPOW.92 and POWSIM without any preliminary models of the molecules, and by Patterson search methods via DIRDIF96 and PATSEE with the use of rigid fragments from each of the molecules. The neutron patterns allowed (I) and (II) to be solved using the grid search procedure and correct initial models of the molecules including H atoms. The results obtained from powder patterns measured on different devices demonstrate the high level of reproducibility and reliability of various powder software and equipment, with a certain preference for synchrotron facilities.

Crystal structure of strontium hydrogen citrate monohydrate, Sr(HC6H5O7)(H2O)

2021 ◽  
pp. 1-9
Author(s):  
James A. Kaduk
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Density Functional ◽  
Water Molecules ◽  
Powder Diffraction Data ◽  
Unknown Compound ◽  
Coordination Polyhedra ◽  
X Ray ◽  
Carboxylic Acid Groups ◽  
Triclinic Unit Cell

The crystal structure of strontium hydrogen citrate monohydrate has been solved using laboratory X-ray powder diffraction data, refined using both laboratory and synchrotron data, and optimized using density functional techniques. Strontium hydrogen citrate monohydrate crystallizes in space group C2/c (#15) with a = 25.15601(17), b = 10.90724(6), c = 6.37341(4) Å, β = 91.9846(6)°, V = 1747.704(12) Å3, and Z = 8. The Sr coordination and the hydrogen bonding result in a layered structure. The SrO8 coordination polyhedra share edges to form corrugated layers parallel to the bc-plane. Hydrogen bonds between the carboxylic acid groups and water molecules link the layers. Intermolecular hydroxyl–carboxyl hydrogen bonds also link the layers in a ring pattern with a graph set symbol R2,2(12). After storage for 2 years, partial re-crystallization occurred, to an as-yet unknown compound with a triclinic unit cell.

A grid search procedure of positioning a known molecule in an unknown crystal structure with the use of powder diffraction data

1998 ◽  
Vol 213 (1) ◽  
pp. 1-3 ◽  
Author(s):  
V. V. Chernyshev ◽  
H. Schenk
Keyword(s):  
Crystal Structure ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Neutron Powder Diffraction ◽  
Molecular Structures ◽  
Search Procedure ◽  
Grid Search ◽  
Powder Diffraction Data ◽  
X Ray ◽  
Neutron Powder Diffraction Data

AbstractAn efficient grid search procedure successfully applied to the solution of three unknown molecular structures from X-ray and neutron powder diffraction data is presented.

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