Structural disorder of a new zeolite-like lithosilicate, K2.6Li5.4[Li4Si16O38]·4.3H2O

2006 ◽  
Vol 62 (1) ◽  
pp. 42-51 ◽  
Author(s):  
So-Hyun Park ◽  
Hans Boysen ◽  
John B. Parise
Keyword(s):  
Diffraction Data ◽  
Structural Disorder ◽  
The Other ◽  
Third Generation ◽  
Framework Structure ◽  
X Ray Diffraction ◽  
Single Crystal Diffraction ◽  
X Ray ◽  
Fibrous Zeolites ◽  
New Framework

The framework structure of the synthetic microporous lithosilicate RUB-30 (K2.6Li5.4[Li4Si16O38]·4.3H2O) is similar to that of the fibrous zeolites such as natrolite, edingtonite and thomsonite, since all their frameworks include the same secondary structural building unit, the so-called 4–1 T 5O10 cluster of tetrahedra. Unique to the structure of RUB-30, each 4–1 unit consists of a LiSi4O10 moiety within which the single [LiO4] tetrahedron is strictly segregated from the other four [SiO4] tetrahedra. The connection of neighboring 4–1 units through edge-sharing [LiO4] tetrahedra results in a new framework topology. The present work reports an `average' structure of RUB-30 solved by synchrotron X-ray single-crystal diffraction data collected at a second-generation source. A superstructure with a × 2b × c (relative to the subcell quoted above) could be seen in X-ray diffraction data collected with better resolution and higher brightness at a third generation source. Diffuse streaks along k with l = odd and unusual superstructure hkl reflections, with k = odd and l = odd only, indicate a more complicated real structure of the material. To explain this observation we propose two different structure types which are statistically, but coherently, intergrown in RUB-30.

M3+(H2AsO4)(H2As2O7) (M3+= Al, Ga) and In2(H2AsO4)2(H2As2O7)2: a new layer structure type and a new framework structure type containing the rare H2As2O72−group

2017 ◽  
Vol 73 (8) ◽  
pp. 600-608 ◽  
Author(s):  
Karolina Schwendtner ◽  
Uwe Kolitsch
Keyword(s):  
Hydrogen Bonds ◽  
Room Temperature ◽  
Layer Structure ◽  
Structure Type ◽  
Three Dimensions ◽  
Framework Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Third ◽  
New Framework

The crystal structures of hydrothermally synthesized aluminium dihydrogen arsenate(V) dihydrogen diarsenate(V), Al(H2AsO4)(H2As2O7), gallium dihydrogen arsenate(V) dihydrogen diarsenate(V), Ga(H2AsO4)(H2As2O7), and diindium bis[dihydrogen arsenate(V)] bis[dihydrogen diarsenate(V)], In2(H2AsO4)2(H2As2O7)2, were determined from single-crystal X-ray diffraction data collected at room temperature. The first two compounds are representatives of a novel sheet structure type, whereas the third compound crystallizes in a novel framework structure. In all three structures, the basic building units areM3+O6octahedra (M= Al, Ga, In) that are connectedviaone H2AsO4−and two H2As2O72−groups into chains, and furtherviaH2As2O72−groups into layers. In Al/Ga(H2AsO4)(H2As2O7), these layers are interconnected by weak-to-medium–strong hydrogen bonds. In In2(H2AsO4)2(H2As2O7)2, the H2As2O72−groups link the chains in three dimensions, thus creating a framework topology, which is reinforced by weak-to-medium–strong hydrogen bonds. The three title arsenates represent the first compounds containing both H2AsO4−and H2As2O72−groups.

A synchrotron X-ray diffraction analysis of near-stoichiometric LiNbO3

2001 ◽  
Vol 216 (8) ◽  
Author(s):  
B. Etschmann ◽  
N. Ishizawa ◽  
V. Streltsov ◽  
S. Oishi
Keyword(s):  
Single Crystal ◽  
Diffraction Analysis ◽  
Diffraction Data ◽  
X Ray Diffraction ◽  
Single Crystal Diffraction ◽  
X Ray

AbstractSingle-crystal diffraction data was collected at 120 and 294 K for an approximately spherical LiNbO

The perchlorotriphenylmethyl (PTM) radical

2013 ◽  
Vol 69 (3) ◽  
pp. 255-257 ◽  
Author(s):  
Judith Guasch ◽  
Xavier Fontrodona ◽  
Imma Ratera ◽  
Concepció Rovira ◽  
Jaume Veciana
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Diffraction Data ◽  
The Other ◽  
X Ray Diffraction ◽  
Monoclinic Symmetry ◽  
Steric Strain ◽  
High Chemical ◽  
X Ray ◽  
Cl Atoms

In spite of the considerable understanding and development of perchlorotriphenylmethyl (PTM) radical derivatives, the preparation of crystals of the pure unsubstituted PTM radical, C19Cl15, suitable for single-crystal X-ray diffraction has remained a challenge since its discovery, and only two studies dealing with the crystal structure of the unsubstituted PTM radical have been published. In one study, the radical forms clathrates with aromatic solvents [Veciana, Carilla, Miravitlles & Molins (1987).J. Chem. Soc. Chem. Commun.pp. 812–814], and in the other the structure was determinedab initiofrom powder X-ray diffraction data [Rius, Miravitlles, Molins, Crespo & Veciana (1990).Mol. Cryst. Liq. Cryst.187, 155–163]. We report here the preparation of PTM crystals for single-crystal X-ray diffraction and their resolution. The structure, which shows monoclinic symmetry (C2/c), revealed a nonsymmetric molecular propeller conformation (D3symmetry) caused by the steric strain between theortho-Cl atoms, which protect the central C atom (sp2-hybridization and major spin density) and give high chemical and thermal persistence to the PTM. The supramolecular structure of PTM shows short Cl...Cl intermolecular interactions and can be described in terms of layers formed by rows of molecules positioned in a head-to-tail manner along thecaxis.

Formamidinhim-Hexachloroferrat(III) Synthese und Kristallstruktur / Formamidinium-Hexachloroferrate(III) Synthesis and Crystal Structure

1985 ◽  
Vol 40 (3) ◽  
pp. 443-446 ◽  
Author(s):  
Udo Demant ◽  
Elke Conradi ◽  
Ulrich Müller ◽  
Kurt Dehnicke
Keyword(s):  
Crystal Structure ◽  
Diffraction Data ◽  
The Other ◽  
X Ray Diffraction ◽  
Synthesis And Crystal Structure ◽  
Space Group ◽  
X Ray ◽  
Positional Disorder ◽  
Lattice Constants ◽  
Bond Lengths

[HC(NH2)2]3FeCl6 was obtained together with other products from the reaction of S4N4 with HCl in H2CCl2 in the presence of FeCl3. Its crystal structure was determined from X-ray diffraction data (473 independent observed reflexions, R = 0.047). Lattice constants: a = 961.6, c = 876.4 pm; tetragonal, space group P42/m, Z = 2. Of the two crystallographically independent formamidinium ions HC(NH2)2⊕, one exhibits positional disorder; the other one has C-N bond lengths of 128 pm. The FeCl63⊖ ions have symmetry C2h, but the deviation from Oh is small.

Statistical Inference, Size Distributions and Peak Broadening in Finite Crystals

1987 ◽  
Vol 2 (4) ◽  
pp. 220-224 ◽  
Author(s):  
A. G. Alvarez ◽  
R. D. Bonetto ◽  
D. M. A. Guérin ◽  
A. Plastino ◽  
L. Rebollo Neira
Keyword(s):  
Information Theory ◽  
Statistical Inference ◽  
Diffraction Data ◽  
Crystal Size ◽  
The Other ◽  
Size Distributions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Crystal Size Distributions ◽  
Peak Broadening

AbstractCalculations of crystal size distributions in oriented clays (montmorillonite and kaolinite) are carried out utilizing X-ray diffraction data together with a method based on information theory. Two different procedures for dealing with the available data are compared. One of them involves some points of the corresponding spectrum, the other correlates the data by means of their moments.

scholarly journals The pseudo-single-crystal method: a third approach to crystal structure determination

2009 ◽  
Vol 42 (3) ◽  
pp. 535-537 ◽  
Author(s):  
Tsunehisa Kimura ◽  
Chengkang Chang ◽  
Fumiko Kimura ◽  
Masataka Maeyama
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Diffraction Data ◽  
X Ray Diffraction ◽  
Single Crystal Diffraction ◽  
Uv Curable ◽  
X Ray ◽  
Novel Method ◽  
Good Agreement ◽  
Pseudo Single Crystal

A novel method that enables single-crystal diffraction data to be obtained from a powder sample is presented. A suspension of LiCoPO4microrods was subjected to a frequency-modulated dynamic elliptical magnetic field to align the microrods; the alignment achieved was consolidated by photopolymerization of the suspending UV-curable monomer. The composite thus obtained (referred to as a pseudo single crystal) gave rise to X-ray diffraction data from which the crystal structure was solved using the standard method for single-crystal X-ray analyses. The structure determined was in good agreement with that reported using a conventional single crystal.

Structural Disorder and Thermal Dilatation Behavior in Cr-Doped Mullite

1994 ◽  
Vol 346 ◽  
Author(s):  
M.P. Villar ◽  
J.M. Geraldia ◽  
L. Gago-Duport
Keyword(s):  
Thermal Expansion ◽  
Diffraction Data ◽  
Chromium Content ◽  
Sol Gel ◽  
Structural Disorder ◽  
Lattice Parameters ◽  
X Ray Diffraction ◽  
X Ray ◽  
Anisotropic Expansion ◽  
Thermal Dilatation

ABSTRACTLattice parameters of some different chromium-doped mullites obtained by a sol-gel route and sintered at 1650° C have been determined from X-Ray Diffraction data as a function of both temperature and Cr contents. Profile refinements on the X-ray diffraction diagrams have been carried out, showing that, at temperatures between 800° and 1535° C, an anisotropic thermal expansion takes place for the a and b lattice parameters of the Cr-doped mullite. We show that this anisotropic expansion is dependent on the temperature increase and the chromium content for the different compositions of the mullite crystals.

Refinement of d-AlNico Quasicrystal Structures

2000 ◽  
Vol 643 ◽  
Author(s):  
Hiroyuki Takakura ◽  
Akiji Yamamoto ◽  
An Pang Tsai
Keyword(s):  
Chemical Composition ◽  
High Resolution ◽  
Single Crystal ◽  
Diffraction Data ◽  
The Other ◽  
Structure Model ◽  
X Ray Diffraction ◽  
Data Set ◽  
X Ray ◽  
High Resolution Images

AbstractThe models of decagonal Al72Ni20Co8 quasicrystal with the space group of P105/mmc were refined on the basis of single crystal x-ray diffraction data set using the 5D description. The results of a structure model derived from Al13Fe4-type approximant crystal and Burkov model are compared. The former gives ω R=0.045 and R=0.063 for 449 reflections with 103 parameters and a resonable chemical composition of Al71.2TM28.8 (TM=transition metals). The projected structure in consistent with high resolution images of this material. On the other hand, the latter gives ωR=0.161 and R=0.193 for 55 parameters and a compositon of Al64.6TM35.1.

scholarly journals Effect of Crystallinity of β- and βbc-Nickel Hydroxide Samples on Chemical Cycling

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Ramesh Thimmasandra Narayan
Keyword(s):  
Diffraction Data ◽  
Nickel Hydroxide ◽  
Ammonium Hydroxide ◽  
Structural Disorder ◽  
Chemical Oxidation ◽  
Cobalt Hydroxide ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diffraction Patterns ◽  
Nickel Oxyhydroxide

β-phases of nickel hydroxide and cobalt hydroxide samples crystallize in cadmium iodide type structure. β-cobalt hydroxide on oxidation generates β-CoOOH which crystallized in 3R1 polytype while the structure of β-phase of NiOOH polytype is less well understood. β- and βbc-phases of nickel hydroxide samples were prepared by using ammonium hydroxide and sodium hydroxide as precipitating agents. Powder X-ray diffraction data shows that β-phase of nickel hydroxide is perfectly crystalline in nature while βbc-phase of nickel hydroxide is poorly ordered. β- and βbc-phases of nickel hydroxide samples were subjected to chemical oxidation using sodium hypochlorite. The oxidized phases of β- and βbc-phases of nickel oxyhydroxide are highly disordered and the broadening of reflections in the powder X-ray diffraction patterns is due to the presence of structural disorder, variations in the crystallite size, and strain. On reduction of β- and βbc-phases of nickel oxyhydroxide, the powder X-ray diffraction patterns visually match the powder X-ray diffraction data of the pristine phases of β- and βbc-phases of nickel hydroxide indicating that the β-phase of nickel hydroxide does not transform to βbc-phase of nickel hydroxide, but the particle sizes are significantly affected.

scholarly journals Single-crystal diffraction data from powder samples via SFX

2014 ◽  
Vol 70 (a1) ◽  
pp. C1449-C1449
Author(s):  
Tao Zhang ◽  
Shifeng Jin ◽  
Yuanxin Gu ◽  
Yao He ◽  
Haifu Fan
Keyword(s):  
Single Crystal ◽  
Diffraction Data ◽  
Three Dimensional ◽  
Monte Carlo Integration ◽  
X Ray Diffraction ◽  
Single Crystal Diffraction ◽  
Single Experiment ◽  
X Ray ◽  
Powder Samples ◽  
Diffraction Patterns

With the serial femtosecond crystallography (SFX) [1] using hard X-ray free-electron laser as light source, it is possible to obtained three-dimensional single-crystal diffraction data from powder samples consisting of submicron crystal grains. This offers two advantages. First, complicated crystal structures far beyond the ability of powder X-ray diffraction analysis now can be solved easily; second, mixtures of two or more crystalline components can be examined in a single experiment. The percentage of each component can be determined accurately and the crystal structure of them can be solved readily. Simulating calculations were performed with a mixture of two different kinds of zeolites. The program suite CrystFEL [2] was used for simulating SFX diffraction patterns, diffraction indexing and Monte-Carlo integration of diffraction intensities. The program suite SHELX [3] was used for structure determination. Satisfactory results have been obtained and will be discussed in detail.

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