Synthesis and crystal structure of Na3.5Cr1.5Co0.5(PO4)3 phosphate

2006 ◽  
Vol 21 (3) ◽  
pp. 210-213 ◽  
Author(s):  
Mohamed Chakir ◽  
Abdelaziz El Jazouli ◽  
Jean-Pierre Chaminade
Keyword(s):  
Crystal Structure ◽  
Three Dimensional ◽  
Unit Cell ◽  
X Ray Diffraction ◽  
Synthesis And Crystal Structure ◽  
Space Group ◽  
X Ray ◽  
Hexagonal Unit Cell ◽  
Cell Dimensions ◽  
Unit Cell Dimensions

A new Nasicon phosphates series [Na3+xCr2−xCox(PO4)3(0⩽x⩽1)] was synthesized by a coprecipitation method and structurally characterized by powder X-ray diffraction. The selected compound Na3.5Cr1.5Co0.5(PO4)3 (x=0.5) crystallizes in the R3c space group with the following hexagonal unit-cell dimensions: ah=8.7285(3) Å, ch=21.580(2) Å, V=1423.8(1) Å3, and Z=6. This three-dimensional framework is built of PO4 tetrahedra and Cr∕CoO6 octahedra sharing corners. Na atoms occupy totally M(1) sites and partially M(2) sites.

X-Ray Crystal Structure of [Rh(OH2)6](ClO4)3.3H2O

1989 ◽  
Vol 42 (11) ◽  
pp. 2051 ◽  
Author(s):  
GD Fallon ◽  
L Spiccia
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Unit Cell ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Octahedral Sites ◽  
Cell Dimensions ◽  
Unit Cell Dimensions

The crystal structure of [Rh(OH2)6](ClO4)3.3H2O has been determined by single-crystal X-ray diffraction and found to be isomorphous with that of M(ClO4)2.6H2O (M= Fe, Zn, Mn, Co, Ni) and LiClO4.3H2O. Crystal: are hexagonal, space group P63mc with unit cell dimensions a 7.817(2) and c 5.208(1) �. The lattice consists of a uniform arrangement of H2O and ClO4- groups with the RhIII centre occupying 1/3 of the octahedral sites formed by the H2O groups. The RhIII is not situated at the centre of the octahedron. However, the two Rh-O distances [2.128(6) and 2.136(6) �] may be considered identical, i.e. within the errors.

The crystal structure of gersdorffite (III), a distorted and disordered pyrite structure

1968 ◽  
Vol 36 (283) ◽  
pp. 940-947 ◽  
Author(s):  
P. Bayliss ◽  
N. C. Stephenson
Keyword(s):  
Crystal Structure ◽  
Metal Atom ◽  
Diffraction Data ◽  
Three Dimensional ◽  
Unit Cell ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Partially Ordered ◽  
The Ideal

SummaryThe crystal structure of gersdorffite (III) has been examined with three-dimensional Weissenberg X-ray diffraction data. The unit cell is isometric with a 5·6849 ± 0·0003 Å, space group PI, and four formula units per cell. This structure has the sulphur and arsenic atoms equally distributed over the non-metal atom sites of pyrite. All atoms show significant random displacements from the ideal pyrite positions to produce triclinic symmetry, which serves to distinguish this mineral from a disordered cubic gersdorffite (II) and a partially ordered cubic gersdorffite (I). Factors responsible for the atomic distortions are discussed.

Die Kristallstruktur von Methyltriphenylphosphoniumhexachlorotitanat [MePh3P]2TiCl6 / The Crystal Structure of Methyltriphenylphosphonium Hexachlorotitanate

1981 ◽  
Vol 36 (2) ◽  
pp. 135-137 ◽  
Author(s):  
Evamarie Hey ◽  
Ulrich Müller
Keyword(s):  
Crystal Structure ◽  
Diffraction Data ◽  
Unit Cell ◽  
Distorted Octahedron ◽  
Inversion Center ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Cell Dimensions

The crystal structure of [MePh3P]2TiCl6 was determined from X-ray diffraction data and refined to a residual index of R = 0.065. It crystallizes in the space group P2i/n with two formula units per unit cell; the cell dimensions are a - 921, b = 1314, c = 1648 pm and y - 100.87°. The TiCl62- ion occupies an inversion center and has the shape of a slightly distorted octahedron with Ti-Cl distances between 233 and 235 pm.

Crystal structure of Al5O3N3 (15R)

2017 ◽  
Vol 32 (S1) ◽  
pp. S2-S5 ◽  
Author(s):  
Jacek Podwórny ◽  
Alicja Pawełek ◽  
Jerzy Czechowski
Keyword(s):  
Crystal Structure ◽  
Structure Determination ◽  
Structural Model ◽  
Stoichiometric Composition ◽  
Unit Cell ◽  
Second Phase ◽  
Space Group ◽  
X Ray ◽  
Cell Dimensions ◽  
Unit Cell Dimensions

Having synthesised an AlON-bonded ceramic corundum material, Al5O3N3 (15R) polytype coexisting with α-Al2O3 was identified. The sample was prepared from an alumina-rich mixture of Al2O3 and AlN substrates and fired at 1650 °C in a nitrogen atmosphere. Using the X-ray external standard quantitative method, one of the reaction products, α-Al2O3, was quantified. From the remaining substrates the stoichiometric composition of the second phase was calculated. The applied method of crystal structure determination consisted of three stages. In the first stage, the Le Bail method of X-ray pattern decomposition was used for the extraction of Al5O3N3 (15R) diffraction lines from a two-phase diffractogram. The space group and unit-cell dimensions from the isostructural SiAl4O2N4 SiAlON phase, producing the same X-ray pattern, were used as input data. Next, the direct structure determination in real space was applied for initial structural model derivation, which was followed by Rietveld refinement. The solved crystal structure of Al5O3N3 (15R), except the stacking sequence, proved to be closely related to the structure of Al7O3N5 (21R) polytype. The Al5O3N3 (15R) is trigonal with space group R-3m, unit-cell dimensions a0 = 3.0128 Å, c0 = 41.8544 Å, and volume V = 329.00 Å3. The model of Al5O3N3 (15R) polytype structure has positional disordering in one of three (6c) Al sites, which leads to stacking faults in six tetrahedral layers. Every third tetrahedron from LR3 and LR4, LR8 and LR9, LR13 and LR14 layers is rotated by 180°.

Structural parameters: Analysis of results

2010 ◽  
Author(s):  
Jenny Pickworth Glusker ◽  
Kenneth N. Trueblood
Keyword(s):  
Crystal Structure ◽  
Structural Parameters ◽  
Three Dimensional ◽  
Molecular Geometry ◽  
Unit Cell ◽  
Space Group ◽  
Cell Dimensions ◽  
Information File ◽  
The Individual ◽  
Unit Cell Dimensions

The results of an X-ray structure analysis are coordinates of the individual, chemically identified atoms in each unit cell, the space group (which gives equivalent positions), and displacement parameters that may be interpreted as indicative of molecular motion and/or disorder. Such data obtained from crystal structure analyses may be incorporated into a CIF or mmCIF (Crystallographic Information File or Macromolecular Crystallographic Information File). These ensure that the results of crystal structure analyses are usefully archived. There are many checks that the crystallographer can make to ensure that the CIF or mmCIF file is correctly informative. For example, the automated validation program PLATON (Spek, 2003) checks that all data reported are up to the standards required for publication by the International Union of Crystallography. It does geometrical calculations on the structure, illustrates the results, finds if any symmetry has been missed, investigates any twinning, and checks if the structure has already been reported. We now review the ways in which these atomic parameters can be used to obtain a three-dimensional vision of the entire crystal structure. When molecules crystallize in an orthorhombic, tetragonal, or cubic unit cell it is reasonably easy to build a model using the unit-cell dimensions and fractional coordinates, because all the interaxial angles are 90◦. However, the situation is more complicated if the unit cell contains oblique axes and it is often simpler to convert the fractional crystal coordinates to orthogonal coordinates before calculating molecular geometry. The equations for doing this for bond lengths, interbond angles, and torsion angles are presented in Appendix 12. If the reader wishes to compute interatomic distances directly, this is also possible if one knows the cell dimensions (a, b, c, ∝ , β , γ ,), the fractional atomic coordinates (x, y, z for each atom), and the space group.

scholarly journals Molekül- und Kristallstruktur von C7H7Mo(CO)2-SnCl3 / The Crystal Structure of C7H7Mo(CO)2-SnCl3

1975 ◽  
Vol 30 (1-2) ◽  
pp. 22-25 ◽  
Author(s):  
M. L. Ziegler ◽  
H.-E. Sasse ◽  
B. Nuber
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Title Compound ◽  
Three Dimensional ◽  
Unit Cell ◽  
Fourier Methods ◽  
X Ray ◽  
Cell Dimensions ◽  
Unit Cell Dimensions ◽  
Group D

The structure of the title compound has been determined from three dimensional X-ray data by Patterson and Fourier methods. The crystals are orthorombic, with unit cell dimensions a = 1181,50 pm, b = 943,68 pm, c = 1181,50 pm, space group D2h16 and Z = 4. Least squares refinement, by use of 1540 independent reflections measured on a diffractometer has reached R = 5,9%.There are discrete C7H7Mo(CO)2 SnCl3 molecules, the molybdenum-tin bond has been dicussed together with the corresponding bonds in other C7H7Mo(CO)2 SnR3 compounds.

Synthese und Kristallstruktur von MoCl4(DME) · 15-Krone-5 und MoCl4(DME) (DME = 1,2-Dimethoxyethan) / Synthesis and Crystal Structure of MoCl4(DME) · 15-Crown-5 and MoCl4(DME) (DME = 1,2-Dimethoxyethane)

1991 ◽  
Vol 46 (3) ◽  
pp. 307-314 ◽  
Author(s):  
Evamarie Hey-Hawkins ◽  
Hans Georg von Schnering
Keyword(s):  
Crystal Structure ◽  
Magnetic Properties ◽  
Structure Determination ◽  
Unit Cell ◽  
Crystal Data ◽  
Synthesis And Crystal Structure ◽  
Space Group ◽  
X Ray ◽  
Cell Dimensions ◽  
Work Up

NaSi reacts with MoCl5 and 15-crown-5 in toluene with reduction of Mo(V) to Mo(IV). Work-up in DME yields MoCl4(DME)· 15-crown-5 (1). MoCl4(DME) (2) is prepared more conveniently from MoCl5/DME. 1 and 2 were characterized spectroscopically and by X-ray structure determination. Crystal data: 1, space group P212121 (No. 19), Z = 4, 2765 observed independent reflexions, R = 0.026, cell dimensions (110 K): a = 16.292(4), b = 12.884(3), c = 10.452(2) Å. 2, space group I4̄2d (No. 122), Z = 8, 558 observed independent reflexions, R = 0.037, cell dimensions (292 K): a = b = 9.562(2), c = 23.777(6)Å. The MoCl4(DME) molecule of 1 and 2 forms a distorted octahedron. There are four non-coordinating 15-crown-5 molecules present in the unit cell of 1. The UV/VIS spectrum and the magnetic properties of 2 are discussed.

The Crystal Structure of Vanillosmopsis-Derived (-) α-Bisabolol p-Phenylazophenylurethane

1989 ◽  
Vol 42 (11) ◽  
pp. 2041 ◽  
Author(s):  
RM Carman ◽  
WT Robinson ◽  
MD Sutherland
Keyword(s):  
Crystal Structure ◽  
Melting Point ◽  
Diffraction Pattern ◽  
Optical Rotation ◽  
Unit Cell ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cell Dimensions ◽  
Unit Cell Dimensions

The p-phenylazophenylurethane of Vanillosmopsis-derived (-)-α-bisabolol has unit cell dimensions and an X-ray diffraction pattern identical with those reported for the p-phenylazophenylurethane of Matricaria-derived (-)-α-bisabolol, despite having a higher melting point and different optical rotation.

Darstellung und Röntgenstrukturanalyse von (CH3)3C-C7H7Mo(CO)3 (1-6- η-7-tert-Butyl-cycloheptatrien)(tricarbonyl)molybdän(0) / Synthesis and Crystal Structure of (CH3)3C-C7H7Mo(CO)3 (1-6-η-7-tert-Butyl-cycloheptatriene)(tricarbonyl)molybdenum(0)

1975 ◽  
Vol 30 (9-10) ◽  
pp. 699-709 ◽  
Author(s):  
Peter O. Tremmel ◽  
Klaus Weidenhammer ◽  
Henning Wienand ◽  
Manfred L. Ziegler
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Title Compound ◽  
Three Dimensional ◽  
Synthesis And Crystal Structure ◽  
Fourier Methods ◽  
X Ray ◽  
Tert Butyl ◽  
Cell Dimensions ◽  
Unit Cell Dimensions

The title compound has been synthesized by three different methods and its structure determined from three dimensional X-ray data by Patterson and Fourier methods. The crystals are triclinic with unit cell dimensions a = 1022.60 ± 0.07 pm, b = 638.69 ± 0.27 pm, c = 1478.00 ± 0.19 pm, α = 78.48 ±0.02°, β = 131.049 ± 0.008°, γ = 87.16 ± 0.03 °, space group Ci1—PT and Z = 2. Least squares refinement by use of 2160 independent reflections measured on a diffractometer has reached R = 5.4%.There are discrete (CH3)3C—C7H7Mo(CO)3 molecules, the central molybdenum atom is octahedrally coordinated.

Kristall- und Molekülstruktur von bis -Methallylnickel Ni[(CH2)2C · CH]2

1965 ◽  
Vol 122 (1-6) ◽  
pp. 60-72
Author(s):  
Rüdiger Uttech ◽  
Hans Dietrich
Keyword(s):  
Crystal Structure ◽  
Diffraction Data ◽  
Three Dimensional ◽  
Unit Cell ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray

Abstract The crystal structure of bis-methallylnickel has been determined from three-dimensional x-ray diffraction data. The space group is P21/c-C5 2h with α = 6.05; 6 = 13,48; c = 5.83 Å; β = 117.1°. The unit cell contains 2 molecules with Ni in centres of symmetry. The methallyl groups are symmetrically bonded to the nickel in an anti-sandwich arrangement. This causes the intramolecular symmetry to be 2/m. The methallyl groups are found to be nonplanar and the Ni-C bonds are quite short (average 2.02 Å).

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