Determination of large crystal structures by combined x-ray diffraction and electron microscopy

1967 ◽  
Vol 2 (1) ◽  
pp. 55-68 ◽  
Author(s):  
J.A. Kohn ◽  
D.W. Eckart ◽  
C.F. Cook
Keyword(s):  
Electron Microscopy ◽  
Crystal Structures ◽  
X Ray Diffraction ◽  
Large Crystal ◽  
X Ray

scholarly journals Twinning in Zr-Based Metal-Organic Framework Crystals

Chemistry ◽  
2020 ◽  
Vol 2 (3) ◽  
pp. 777-786
Author(s):  
Sigurd Øien-Ødegaard ◽  
Karl Lillerud
Keyword(s):  
Crystal Structures ◽  
Metal Organic Framework ◽  
Special Importance ◽  
X Ray Diffraction ◽  
X Ray ◽  
Metal Organic ◽  
Ab Initio Structure ◽  
Crystal Twinning ◽  
Organic Framework

Ab initio structure determination of new metal-organic framework (MOF) compounds is generally done by single crystal X-ray diffraction, but this technique can yield incorrect crystal structures if crystal twinning is overlooked. Herein, the crystal structures of three Zirconium-based MOFs, that are especially prone to twinning, have been determined from twinned crystals. These twin laws (and others) could potentially occur in many MOFs or related network structures, and the methods and tools described herein to detect and treat twinning could be useful to resolve the structures of affected crystals. Our results highlight the prevalence (and sometimes inevitability) of twinning in certain Zr-MOFs. Of special importance are the works of Howard Flack which, in addition to fundamental advances in crystallography, provide accessible tools for inexperienced crystallographers to take twinning into account in structure elucidation.

Laccase Biosensor Based on Ag-Doped TiO2 Nanoparticles on CuCNFs for the Determination of Hydroquinone

NANO ◽  
2016 ◽  
Vol 11 (12) ◽  
pp. 1650132 ◽  
Author(s):  
Jie Yang ◽  
Dawei Li ◽  
Zengyuan Pang ◽  
Qufu Wei
Keyword(s):  
Electron Microscopy ◽  
Storage Stability ◽  
Electrochemical Impedance ◽  
The Novel ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
New Material ◽  
And Storage

A novel nanomaterial composed of copper and carbon nanofibers (CuCNFs) decorated with Ag-doped TiO2 (Ag–TiO[Formula: see text] nanoparticles was prepared through electrospinning, carbonization and solvothermal treatment. The composites were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and electrochemical impedance spectroscopy (EIS). The obtained composites were mixed with laccase and Nafion to construct novel hydroquinone biosensor. The electrochemical behavior of the novel biosensor was studied using cyclic voltammetry (CV) and chronoamperometry. The results demonstrated that the biosensor possessed a wide detection linear range (1.20–176.50[Formula: see text][Formula: see text]M), a good selectivity, repeatability, reproducibility and storage stability. This work provides a new material to design more efficient laccase (Lac) based biosensor for hydroquinone detection.

Study of an Energetic-oxidant Co-crystal: Preparation, Characterisation, and Crystallisation Mechanism

2017 ◽  
Vol 67 (5) ◽  
pp. 510 ◽  
Author(s):  
Han Gao ◽  
Wei Jiang ◽  
Jie Liu ◽  
Gazi Hao ◽  
Lei Xiao ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Differential Scanning Calorimetry ◽  
Diffraction Spectrum ◽  
Solvent Evaporation Method ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Scanning Electron

<p>An energetic co-crystal consisting of the most promising military explosive 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20) and the most well-known oxidant applied in propellants ammonium perchlorate has been prepared with a simple solvent evaporation method. Scanning electron microscopy revealed that the morphology of co-crystal differs greatly from each component. The X-ray diffraction spectrum, FTIR, Raman spectra, and differential scanning calorimetry characterisation further prove the formation of the co-crystal. The result of determination of hygroscopic rate indicated the hygroscopicity was effectively reduced. At last, the crystallisation mechanism has been discussed.</p>

Estimation of Quartz in Small Biological Specimens with Transmission Electron Microscopy at 100 KV

1974 ◽  
Vol 32 ◽  
pp. 70-71
Author(s):  
Glenn R. Smith ◽  
Krishna Seshan ◽  
Jerome J. Wesolowski ◽  
Axel G. Berner
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Mass Concentration ◽  
Oxygen Plasma ◽  
Human Lung ◽  
X Ray Diffraction ◽  
X Ray ◽  
Biopsy Specimens ◽  
Transmission Electron

Determination of the mass concentration of quartz in small biopsy specimens for clinical diagnostic purposes often cannot be performed by x-ray diffraction and light microscopy. A technique utilizing transmission electron microscopy (TEM) was used to determine the quartz concentration in a human lung specimen taken from a patient suspected of having silicosis.The sample was prepared for examination by low temperature incineration in an oxygen plasma. The inorganic residue was suspended in 0.5 percent Parlodion in amyl acetate. Grids were coated with the sample suspension and subsequently shadowed with a thin film of carbon. Standard quartz particles were prepared in a similar manner.

Zn-rich smectite from the Silver Coin Mine, Nevada, USA

Clay Minerals ◽  
2015 ◽  
Vol 50 (4) ◽  
pp. 417-430 ◽  
Author(s):  
S. Kaufhold ◽  
G. Färber ◽  
R. Dohrmann ◽  
K. Ufer ◽  
G. Grathoff
Keyword(s):  
Electron Microscopy ◽  
Ir Spectroscopy ◽  
Fine Fraction ◽  
Structural Formula ◽  
X Ray Diffraction ◽  
Geochemical Environment ◽  
X Ray ◽  
Silver Coin ◽  
Transmission Electron

AbstractMore than 100 minerals have been reported from the Silver Coin Mine, Nevada USA; five new minerals have been discovered here, due to the unusual geochemical environment. The present study reports on the investigation of a greenish clayey sample from the Silver Coin Mine. After the separation of a fine fraction to enrich the clay minerals, sauconite, a rare Zn-rich smectite, was found by X-ray diffraction (XRD) and was further characterized by differential thermal analysis (DTA), infrared (IR) spectroscopy and scanning electron microscopy (SEM). The Zn-rich smectite is accompanied by illite, minor kaolinite/halloysite and traces of gibbsite (as was indicated by the IR spectroscopy). The occurrence indicates an acidic environment probably caused by oxidation of sulfides.The determination of the structural formula, to further characterize the Zn-rich smectite, was difficult because of the multi-clay mineral assembly. However, different SEM-EDX (energy dispersive X-ray) approaches as well as transmission electron microscopy (TEM)-EDX analysis helped to characterize the smectite as Al-rich sauconite with some exchangeable K+.

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