Characterization of metamict and glassy phosphates using energy-filtered electron diffraction

1992 ◽  
Vol 50 (2) ◽  
pp. 1274-1275
Author(s):  
A. N. Sreeram ◽  
L. C. Qin ◽  
A. J. Garratt-Reed ◽  
L. W. Hobbs
Keyword(s):  
Electron Diffraction ◽  
Single Crystals ◽  
High Performance ◽  
Three Dimensional ◽  
Distribution Functions ◽  
Phosphate Glasses ◽  
Electron Diffraction Data ◽  
X Ray Diffraction ◽  
Condensed Phosphates ◽  
Lead Pyrophosphate

Lead phosphate glasses have been investigated for decades with respect to fundamental glass properties such as glass transition, devitrification, electrical and optical properties. In these glasses, [PO4] tetrahedra, (like [SiO4] tetrahedra in silicates) can link up together by corner sharing oxygen atoms to form polymerized structures upto and including three dimensional glassy networks. Although, little electron diffraction data on amorphous phosphates is available, radial distribution functions have been generated for lime phosphate glasses and amorphous aluminum phosphates using x-ray diffraction techniques. More recently, Sales et al. have examined near surfaces of single crystals of lead pyrophosphate (Pb2P2O7), rendered aperiodic (metamict) by ion implantation, and lead pyrophosphate glass using high-performance liquid chromatography (HPLC), making use of the fact that condensed phosphates do not alter their state of polymerization when dissolved in aqueous solutions.In our studies, single crystals of Pb2P2O7 were found to be beam stable under 200 keV TEM electrons to an electron fluence > 1027 e/m2 and an ionizing dose > 1014 Gy. This negative radiolytic result leaves ballistic displacement by ions or neutrons as the only route to render the samples metamict.

A complex pseudo-decagonal quasicrystal approximant, Al37(Co,Ni)15.5, solved by rotation electron diffraction

2014 ◽  
Vol 47 (1) ◽  
pp. 215-221 ◽  
Author(s):  
Devinder Singh ◽  
Yifeng Yun ◽  
Wei Wan ◽  
Benjamin Grushko ◽  
Xiaodong Zou ◽  
...  
Keyword(s):  
Electron Diffraction ◽  
Single Crystal ◽  
Diffraction Data ◽  
Three Dimensional ◽  
Basic Structure ◽  
Electron Diffraction Data ◽  
Dimensional Electron ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diffraction Patterns

Electron diffraction is a complementary technique to single-crystal X-ray diffraction and powder X-ray diffraction for structure solution of unknown crystals. Crystals too small to be studied by single-crystal X-ray diffraction or too complex to be solved by powder X-ray diffraction can be studied by electron diffraction. The main drawbacks of electron diffraction have been the difficulties in collecting complete three-dimensional electron diffraction data by conventional electron diffraction methods and the very time-consuming data collection. In addition, the intensities of electron diffraction suffer from dynamical scattering. Recently, a new electron diffraction method, rotation electron diffraction (RED), was developed, which can overcome the drawbacks and reduce dynamical effects. A complete three-dimensional electron diffraction data set can be collected from a sub-micrometre-sized single crystal in less than 2 h. Here the RED method is applied forab initiostructure determination of an unknown complex intermetallic phase, the pseudo-decagonal (PD) quasicrystal approximant Al37.0(Co,Ni)15.5, denoted as PD2. RED shows that the crystal is F-centered, witha= 46.4,b= 64.6,c= 8.2 Å. However, as with other approximants in the PD series, the reflections with oddlindices are much weaker than those withleven, so it was decided to first solve the PD2 structure in the smaller, primitive unit cell. The basic structure of PD2 with unit-cell parametersa= 23.2,b= 32.3,c= 4.1 Å and space groupPnmmhas been solved in the present study. The structure withc= 8.2 Å will be taken up in the near future. The basic structure contains 55 unique atoms (17 Co/Ni and 38 Al) and is one of the most complex structures solved by electron diffraction. PD2 is built of characteristic 2 nm wheel clusters with fivefold rotational symmetry, which agrees with results from high-resolution electron microscopy images. Simulated electron diffraction patterns for the structure model are in good agreement with the experimental electron diffraction patterns obtained by RED.

Single-crystal x-ray diffraction structures of covalent organic frameworks

Science ◽  
2018 ◽  
Vol 361 (6397) ◽  
pp. 48-52 ◽  
Author(s):  
Tianqiong Ma ◽  
Eugene A. Kapustin ◽  
Shawn X. Yin ◽  
Lin Liang ◽  
Zhengyang Zhou ◽  
...  
Keyword(s):  
Single Crystal ◽  
Single Crystals ◽  
Diffraction Data ◽  
General Procedure ◽  
Three Dimensional ◽  
Electron Diffraction Data ◽  
Covalent Organic Frameworks ◽  
X Ray Diffraction ◽  
X Ray

The crystallization problem is an outstanding challenge in the chemistry of porous covalent organic frameworks (COFs). Their structural characterization has been limited to modeling and solutions based on powder x-ray or electron diffraction data. Single crystals of COFs amenable to x-ray diffraction characterization have not been reported. Here, we developed a general procedure to grow large single crystals of three-dimensional imine-based COFs (COF-300, hydrated form of COF-300, COF-303, LZU-79, and LZU-111). The high quality of the crystals allowed collection of single-crystal x-ray diffraction data of up to 0.83-angstrom resolution, leading to unambiguous solution and precise anisotropic refinement. Characteristics such as degree of interpenetration, arrangement of water guests, the reversed imine connectivity, linker disorder, and uncommon topology were deciphered with atomic precision—aspects impossible to determine without single crystals.

Crystal structure analysis of a star-shaped triazine compound: a combination of single-crystal three-dimensional electron diffraction and powder X-ray diffraction

2018 ◽  
Vol 74 (3) ◽  
pp. 287-294 ◽  
Author(s):  
Tatiana E. Gorelik ◽  
Jacco van de Streek ◽  
Herbert Meier ◽  
Lars Andernach ◽  
Till Opatz
Keyword(s):  
Crystal Structure ◽  
Electron Diffraction ◽  
Single Crystal ◽  
Diffraction Data ◽  
Three Dimensional ◽  
Electron Diffraction Data ◽  
Dimensional Electron ◽  
X Ray Diffraction ◽  
Diffraction Profile ◽  
X Ray

The solid-state structure of star-shaped 2,4,6-tris{(E)-2-[4-(dimethylamino)-phenyl]ethenyl}-1,3,5-triazine is determined from a powder sample by exploiting the respective strengths of single-crystal three-dimensional electron diffraction and powder X-ray diffraction data. The unit-cell parameters were determined from single crystal electron diffraction data. Using this information, the powder X-ray diffraction data were indexed, and the crystal structure was determined from the powder diffraction profile. The compound crystallizes in a noncentrosymmetric space group,P212121. The molecular conformation in the crystal structure was used to calculate the molecular dipole moment of 3.22 Debye, which enables the material to show nonlinear optical effects.

scholarly journals Flux Method Growth of Large Size Group IV–V 2D GeP Single Crystals and Photoresponse Application

Crystals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 235
Author(s):  
Shuqi Zhao ◽  
Tongtong Yu ◽  
Ziming Wang ◽  
Shilei Wang ◽  
Limei Wei ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Single Crystals ◽  
High Performance ◽  
Group Iv ◽  
X Ray Diffraction ◽  
High Quality ◽  
Practical Applications ◽  
Large Size ◽  
Growth Method ◽  
Polarized Raman

Two-dimensional (2D) materials driven by their unique electronic and optoelectronic properties have opened up possibilities for their various applications. The large and high-quality single crystals are essential to fabricate high-performance 2D devices for practical applications. Herein, IV-V 2D GeP single crystals with high-quality and large size of 20 × 15 × 5 mm3 were successfully grown by the Bi flux growth method. The crystalline quality of GeP was confirmed by high-resolution X-ray diffraction (HRXRD), Laue diffraction, electron probe microanalysis (EPMA) and Raman spectroscopy. Additionally, intrinsic anisotropic optical properties were investigated by angle-resolved polarized Raman spectroscopy (ARPRS) and transmission spectra in detail. Furthermore, we fabricated high-performance photodetectors based on GeP, presenting a relatively large photocurrent over 3 mA. More generally, our results will significantly contribute the GeP crystal to the wide optoelectronic applications.

scholarly journals Ab initiostructure determination of nanocrystals of organic pharmaceutical compounds by electron diffraction at room temperature using a Timepix quantum area direct electron detector

2016 ◽  
Vol 72 (2) ◽  
pp. 236-242 ◽  
Author(s):  
E. van Genderen ◽  
M. T. B. Clabbers ◽  
P. P. Das ◽  
A. Stewart ◽  
I. Nederlof ◽  
...  
Keyword(s):  
Electron Diffraction ◽  
Room Temperature ◽  
Dynamic Range ◽  
Signal To Noise Ratio ◽  
Three Dimensional ◽  
Direct Methods ◽  
Liquid Nitrogen Temperature ◽  
High Dynamic Range ◽  
Electron Diffraction Data ◽  
High Signal

Until recently, structure determination by transmission electron microscopy of beam-sensitive three-dimensional nanocrystals required electron diffraction tomography data collection at liquid-nitrogen temperature, in order to reduce radiation damage. Here it is shown that the novel Timepix detector combines a high dynamic range with a very high signal-to-noise ratio and single-electron sensitivity, enablingab initiophasing of beam-sensitive organic compounds. Low-dose electron diffraction data (∼0.013 e− Å−2 s−1) were collected at room temperature with the rotation method. It was ascertained that the data were of sufficient quality for structure solution using direct methods using software developed for X-ray crystallography (XDS,SHELX) and for electron crystallography (ADT3D/PETS,SIR2014).

scholarly journals High-Throughput Electron Diffraction Reveals a Hidden Novel Metal-Organic Framework for Electrocatalysis

2021 ◽  
Author(s):  
Meng Ge ◽  
Yanzhi Wang ◽  
Francesco Carraro ◽  
Weibin Liang ◽  
Morteza Roostaeinia ◽  
...  
Keyword(s):  
Electron Diffraction ◽  
High Throughput ◽  
Metal Organic Framework ◽  
Three Dimensional ◽  
Reduction Reaction ◽  
New Materials ◽  
X Ray Diffraction ◽  
Zeolitic Imidazolate Framework ◽  
Wide Range ◽  
Metal Organic

<p>Metal-organic frameworks (MOFs) are known for their versatile combination of inorganic building units and organic linkers, which offers immense opportunities in a wide range of applications. However, many MOFs are typically synthesized as multiphasic polycrystalline powders, which are challenging for studies by X-ray diffraction. Therefore, developing new structural characterization techniques is highly desired in order to accelerate discoveries of new materials. Here, we report a high-throughput approach for structural analysis of MOF nano- and sub-microcrystals by three-dimensional electron diffraction (3DED). A new zeolitic-imidazolate framework (ZIF), denoted ZIF-EC1<a>, </a>was first discovered in a trace amount during the study of a known ZIF-CO<sub>3</sub>-1 material by 3DED. The structures of both ZIFs were solved and refined using 3DED data. ZIF-EC1 has a dense 3D framework structure, which is built by linking mono- and bi-nuclear Zn clusters and 2-methylimidazolates (mIm<sup>-</sup>). With a composition of Zn<sub>3</sub>(mIm)<sub>5</sub>(OH), ZIF-EC1 exhibits high N and Zn densities. We show that the N-doped carbon material derived from ZIF-EC1 is a promising electrocatalysis for oxygen reduction reaction (ORR). The discovery of this new MOF and its conversion to an efficient electrocatalyst highlights the power of 3DED in developing new materials and their applications. </p>

scholarly journals Serial Electron Diffraction Data Processing With diffractem and CrystFEL

2021 ◽  
Vol 8 ◽  
Author(s):  
Robert Bücker ◽  
Pascal Hogan-Lamarre ◽  
R. J. Dwayne Miller
Keyword(s):  
Electron Diffraction ◽  
Data Processing ◽  
Three Dimensional ◽  
Electron Diffraction Data ◽  
New Techniques ◽  
X Ray ◽  
X Ray Crystallography ◽  
Level Of Automation ◽  
Rotation Method ◽  
High Level

Serial electron diffraction (SerialED) is an emerging technique, which applies the snapshot data-collection mode of serial X-ray crystallography to three-dimensional electron diffraction (3D Electron Diffraction), forgoing the conventional rotation method. Similarly to serial X-ray crystallography, this approach leads to almost complete absence of radiation damage effects even for the most sensitive samples, and allows for a high level of automation. However, SerialED also necessitates new techniques of data processing, which combine existing pipelines for rotation electron diffraction and serial X-ray crystallography with some more particular solutions for challenges arising in SerialED specifically. Here, we introduce our analysis pipeline for SerialED data, and its implementation using the CrystFEL and diffractem program packages. Detailed examples are provided in extensive supplementary code.

Ferromagnetic Ordering in the Thallide EuPdTl2

2006 ◽  
Vol 61 (2) ◽  
pp. 159-163 ◽  
Author(s):  
Rainer Kraft ◽  
Sudhindra Rayaprol ◽  
C. Peter Sebastian ◽  
Rainer Pöttgen
Keyword(s):  
Curie Temperature ◽  
Single Crystals ◽  
Magnetic Moment ◽  
Three Dimensional ◽  
X Ray Diffraction ◽  
Zintl Phase ◽  
X Ray ◽  
Divalent Europium ◽  
Ferromagnetic Ordering

AbstractThe new thallide EuPdTl2, synthesized from the elements in a sealed tantalum tube in a highfrequency furnace, was investigated by X-ray diffraction on powders and single crystals: MgCuAl2 type, Cmcm, Z = 4, a = 446.6(1), b = 1076.7(2), c = 812.0(2) pm, wR2 = 0.0632, 336 F2 values, 16 variables. The structure can be considered as an orthorhombically distorted, palladium-filled variant of the binary Zintl phase EuTl2. The palladium and thallium atoms build up a three-dimensional [PdTl2] polyanion with significant Pd-Tl (286 - 287 pm) and Tl-Tl (323 - 329 pm) interactions. The europium atoms fill distorted hexagonal channels of the [PdTl2] polyanion. Susceptibility measurements show a magnetic moment of 7.46(5) μB/Eu atom, indicative of divalent europium. EuPdTl2 is a soft ferromagnet with a Curie temperature of TC = 12.5(5) K.

Growth and structural and physical properties of diisopropylammonium bromide molecular single crystals

2016 ◽  
Vol 49 (6) ◽  
pp. 2053-2062 ◽  
Author(s):  
Harsh Yadav ◽  
Nidhi Sinha ◽  
Sahil Goel ◽  
Abid Hussain ◽  
Binay Kumar
Keyword(s):  
Single Crystals ◽  
Grown Crystal ◽  
Three Dimensional ◽  
Solution Technique ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dielectric Constant And Loss ◽  
Vis Spectroscopy ◽  
Direct Band ◽  
Crystallographic Axes

Large single crystals of the promising molecular organic ferroelectric diisopropylammonium bromide (DIPAB) have been grown by the solution technique. A structural study was performed using single-crystal X-ray diffraction analysis. The twin element of a selected DIPAB crystal was identified by a morphological study. Intermolecular interactions present in the grown crystal were explored by Hirshfeld surface (three-dimensional) and fingerprint plot (two-dimensional) studies. In UV–vis spectroscopy, the DIPAB crystal has shown high transparency with a wide direct band gap of 5.65 eV. In the photoluminescence spectrum, sharp UV and blue emissions were observed at 370, 392, 417 and 432 nm. The electrical properties were investigated by measuring the dielectric constant (∊) and loss (tanδ) of the grown crystal. The DIPAB crystal exhibits a promising piezoelectric charge coefficient (d33) value of 18 pC N−1, which makes it suitable for transducer applications. A high ferroelectric Curie temperature (Tc≃ 425 K) with high remnant polarization (20.52 µC cm−2) and high coercive field (12.25 kV cm−1) were observed in the as-grown crystal. Vickers microhardness analysis shows that the value of Meyer's index (n= 7.27) belongs to the soft material range, which was also confirmed by void analysis along three crystallographic axes. It is shown that the DIPAB crystal has potential for optical, ferroelectric and piezoelectric applications.

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