Atomic structure solution of the complex quasicrystal approximant Al77Rh15Ru8from electron diffraction data

2014 ◽  
Vol 70 (6) ◽  
pp. 999-1005 ◽  
Author(s):  
Shmuel Samuha ◽  
Enrico Mugnaioli ◽  
Benjamin Grushko ◽  
Ute Kolb ◽  
Louisa Meshi
Keyword(s):  
Electron Diffraction ◽  
Structural Model ◽  
Direct Methods ◽  
High Resolution Electron Microscopy ◽  
Single Type ◽  
Electron Diffraction Data ◽  
Decagonal Quasicrystals ◽  
Resolution Electron ◽  
Structure Solution ◽  
Precession Electron Diffraction

The crystal structure of the novel Al77Rh15Ru8phase (which is an approximant of decagonal quasicrystals) was determined using modern direct methods (MDM) applied to automated electron diffraction tomography (ADT) data. The Al77Rh15Ru8E-phase is orthorhombic [Pbma,a= 23.40 (5),b= 16.20 (4) andc= 20.00 (5) Å] and has one of the most complicated intermetallic structures solved solely by electron diffraction methods. Its structural model consists of 78 unique atomic positions in the unit cell (19 Rh/Ru and 59 Al). Precession electron diffraction (PED) patterns and high-resolution electron microscopy (HRTEM) images were used for the validation of the proposed atomic model. The structure of the E-phase is described using hierarchical packing of polyhedra and a single type of tiling in the form of a parallelogram. Based on this description, the structure of the E-phase is compared with that of the ε6-phase formed in Al–Rh–Ru at close compositions.

scholarly journals UsingFOCUSto solve zeolite structures from three-dimensional electron diffraction data

2013 ◽  
Vol 46 (4) ◽  
pp. 1017-1023 ◽  
Author(s):  
Stef Smeets ◽  
Lynne B. McCusker ◽  
Christian Baerlocher ◽  
Enrico Mugnaioli ◽  
Ute Kolb
Keyword(s):  
Electron Diffraction ◽  
Diffraction Data ◽  
Three Dimensional ◽  
Direct Methods ◽  
Electron Diffraction Data ◽  
Chemical Information ◽  
Data Sets ◽  
Dimensional Electron ◽  
Specific Chemical ◽  
Structure Solution

The programFOCUS[Grosse-Kunstleve, McCusker & Baerlocher (1997).J. Appl. Cryst.30, 985–995] was originally developed to solve zeolite structures from X-ray powder diffraction data. It uses zeolite-specific chemical information (three-dimensional 4-connected framework structure with known bond distances and angles) to supplement the diffraction data. In this way, it is possible to compensate, at least in part, for the ambiguity of the reflection intensities resulting from reflection overlap, and the program has proven to be quite successful. Recently, advances in electron microscopy have led to the development of automated diffraction tomography (ADT) and rotation electron diffraction (RED) techniques for collecting three-dimensional electron diffraction data on very small crystallites. Reasoning that such data are also less than ideal (dynamical scattering, low completeness, beam damage) and that this can lead to failure of structure solution by conventional direct methods for very complex zeolite frameworks,FOCUSwas modified to accommodate electron diffraction data. The modified program was applied successfully to five different data sets (four ADT and one RED) collected on zeolites of different complexities. One of these could not be solved completely by direct methods but emerged easily in theFOCUStrials.

Electron Crystallography of Phthalocyanines

1999 ◽  
Vol 03 (07) ◽  
pp. 672-678 ◽  
Author(s):  
J. R. FRYER
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Electron Diffraction ◽  
Diffraction Data ◽  
Structural Information ◽  
High Resolution Electron Microscopy ◽  
Electron Diffraction Data ◽  
Electron Crystallography ◽  
Resolution Electron ◽  
Copper Phthalocyanines

It is shown that it is possible to obtain structural information from small (<100 nm) phthalocyanine crystals by using crystallographic direct phasing methods applied to electron diffraction data. This technique is both quantitative and does not suffer from the difficulties associated with high-resolution electron microscopy. Structural information has been obtained from both tetra- and octa chloro-copper phthalocyanines, and the results compared with the hydrogenated and perchloro members of the series.

Direct space structure solution from precession electron diffraction data: Resolving heavy and light scatterers in Pb13Mn9O25

2010 ◽  
Vol 110 (7) ◽  
pp. 881-890 ◽  
Author(s):  
Joke Hadermann ◽  
Artem M. Abakumov ◽  
Alexander A. Tsirlin ◽  
Vladimir P. Filonenko ◽  
Julie Gonnissen ◽  
...  
Keyword(s):  
Electron Diffraction ◽  
Diffraction Data ◽  
Space Structure ◽  
Electron Diffraction Data ◽  
Structure Solution ◽  
Precession Electron Diffraction

The structure of nano-twinned rhombohedral YCuO2.66 solved by electron crystallography

2019 ◽  
Vol 75 (1) ◽  
pp. 107-112 ◽  
Author(s):  
Holger Klein ◽  
V. Ovidiu Garlea ◽  
Céline Darie ◽  
Pierre Bordet
Keyword(s):  
Electron Diffraction ◽  
Two Dimensions ◽  
Electron Diffraction Data ◽  
Electron Crystallography ◽  
One Dimensional ◽  
X Ray ◽  
Spin Interactions ◽  
Structure Solution ◽  
Precession Electron Diffraction ◽  
Frustrated Spin

In the search for frustrated spin interactions, a YCuO2.66 phase has been synthesized by a treatment under oxygen pressure of YCuO2.5. X-ray powder diffraction and electron diffraction studies have been conducted. Electron diffraction shows that the sample is twinned on a 10 nm scale. Precession electron diffraction data obtained from a twinned crystal was treated in order to obtain intensities corresponding to only one of the orientations of the twins. From this data a structure solution was obtained where, as in YCuO2.5, the Cu atoms form triangular planes. The Cu atoms are linked in two dimensions by oxygen atoms in the present structure whereas in YCuO2.5 they are only linked in one-dimensional chains.

Automated diffraction tomography combined with electron precession: a new tool for ab initio nanostructure analysis

2009 ◽  
Vol 1184 ◽  
Author(s):  
Ute Kolb ◽  
Tatiana Gorelik ◽  
Enrico Mugnaioli
Keyword(s):  
Electron Diffraction ◽  
Ab Initio ◽  
Crystal Structures ◽  
Diffraction Data ◽  
Three Dimensional ◽  
Direct Methods ◽  
Electron Diffraction Data ◽  
Diffraction Tomography ◽  
Diffraction Mode ◽  
Structure Solution

AbstractThree-dimensional electron diffraction data was collected with our recently developed module for automated diffraction tomography and used to solve inorganic as well as organic crystal structures ab initio. The diffraction data, which covers nearly the full relevant reciprocal space, was collected in the standard nano electron diffraction mode as well as in combination with the precession technique and was subsequently processed with a newly developed automated diffraction analysis and processing software package. Non-precessed data turned out to be sufficient for ab initio structure solution by direct methods for simple crystal structures only, while precessed data allowed structure solution and refinement in all of the studied cases.

Structure solution of the new titanate Li4Ti8Ni3O21 using precession electron diffraction

2009 ◽  
Vol 66 (1) ◽  
pp. 60-68 ◽  
Author(s):  
Mauro Gemmi ◽  
Holger Klein ◽  
Amelie Rageau ◽  
Pierre Strobel ◽  
Federic Le Cras
Keyword(s):  
Electron Diffraction ◽  
Three Dimensional ◽  
Direct Methods ◽  
Electron Diffraction Experiment ◽  
Cation Site ◽  
Synchrotron Powder Diffraction ◽  
Edge Sharing Octahedra ◽  
Structure Solution ◽  
Precession Electron Diffraction ◽  
Trigonal Phase

A sample having stoichiometry Li[Ti1.5Ni0.5]O4 has been synthesized to obtain a spinel structure. The resulting crystalline powder revealed a multiphase nature with spinel as the minor phase. The main phase is a new trigonal phase having a = 5.05910 (1), c = 32.5371 (1) Å. The structure has been solved by direct methods working on a three-dimensional set of intensities obtained from a precession electron-diffraction experiment, and refined on synchrotron powder diffraction data in the space group P\bar 3c1. The model consists of hexagonal layers of edge-sharing octahedra occupied either by the heavy cations Ti and Ni, or preferentially by Li. On the basis of cation-site occupancies the stoichiometry becomes Li4Ti8Ni3O21, which is compatible with the microanalysis results.

scholarly journals Combining precession electron diffraction data with X-ray powder diffraction data to facilitate structure solution

2008 ◽  
Vol 41 (6) ◽  
pp. 1115-1121 ◽  
Author(s):  
Dan Xie ◽  
Christian Baerlocher ◽  
Lynne B. McCusker
Keyword(s):  
Electron Diffraction ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Electron Diffraction Data ◽  
Powder Diffraction Data ◽  
Powder Charge ◽  
X Ray ◽  
Structure Solution ◽  
Precession Electron Diffraction ◽  
Using Data

Information derived from precession electron diffraction (PED) patterns can be used to advantage in combination with high-resolution X-ray powder diffraction data to solve crystal structures that resist solution from X-ray data alone. PED data have been exploited in two different ways for this purpose: (1) to identify weak reflections and (2) to estimate the phases of the reflections in the projection. The former is used to improve the partitioning of the reflection intensities within an overlap group and the latter to provide some starting phases for structure determination. The information was incorporated into a powder charge-flipping algorithm for structure solution. The approaches were first developed using data for the moderately complex zeolite ZSM-5, and then tested on TNU-9, one of the two most complex zeolites known. In both cases, including PED data from just a few projections facilitated structure solution significantly.

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