scholarly journals SSZ‐27: A Small‐Pore Zeolite with Large Heart‐Shaped Cavities Determined by Using Multi‐crystal Electron Diffraction

2019 ◽  
Vol 58 (37) ◽  
pp. 13080-13086 ◽  
Author(s):  
Stef Smeets ◽  
Stacey I. Zones ◽  
Dan Xie ◽  
Lukáš Palatinus ◽  
Jesus Pascual ◽  
...  
Keyword(s):  
Electron Diffraction ◽  
Small Pore ◽  
Crystal Electron

scholarly journals SSZ‐27: A Small‐Pore Zeolite with Large Heart‐Shaped Cavities Determined by Using Multi‐crystal Electron Diffraction

2019 ◽  
Vol 131 (37) ◽  
pp. 13214-13220
Author(s):  
Stef Smeets ◽  
Stacey I. Zones ◽  
Dan Xie ◽  
Lukáš Palatinus ◽  
Jesus Pascual ◽  
...  
Keyword(s):  
Electron Diffraction ◽  
Small Pore ◽  
Crystal Electron

Photographical Record of the Dispersion Surface in Rotating Crystal Electron Diffraction Pattern

1968 ◽  
Vol 23 (4) ◽  
pp. 544-549 ◽  
Author(s):  
G. Lehmpfuhl ◽  
A. Reissland
Keyword(s):  
Dynamical System ◽  
Electron Diffraction ◽  
Diffraction Pattern ◽  
Electron Diffraction Pattern ◽  
Plane Waves ◽  
Zone Axis ◽  
System Of Equations ◽  
Wave Fields ◽  
Dispersion Surface ◽  
Crystal Electron

Strong interacting wave fields in a wedge-shaped crystal are separated into different plane waves when leaving the crystal and reveal points on the dispersion surface. By rotating the crystal while moving the film one obtains a photographical record of a section through the dispersion surface which may be compared with theory. An experiment with a macroscopic MgO wedge is reported. The 002 interference with excitation error nearly zero was recorded near the [I10] zone axis while rotating the crystal about the [001] axis. The diagrams are compared with dynamical 17-beam calculations. The results show that a reduction of the infinite dynamical system of equations to 17 equations is correct under these special geometrical conditions.

ZONES: a search/match database for single-crystal electron diffraction

2002 ◽  
Vol 35 (5) ◽  
pp. 552-555 ◽  
Author(s):  
Haskell V. Hart
Keyword(s):  
Analytical Chemistry ◽  
Electron Diffraction ◽  
Personal Computer ◽  
Materials Science ◽  
Crystal Data ◽  
Double Diffraction ◽  
Selected Area Electron Diffraction ◽  
Unit Cells ◽  
Crystal Electron ◽  
Original Crystal

ZONES is a relational database built from NIST Crystal Data for the identification of single crystals by selected area electron diffraction (SAED) and elemental analysis using MicrosoftAccess 97for the personal computer (subsequently converted toAccess 2000). The two largest experimentaldspacings and included angle in a zone are matched against values calculated from reduced unit cells, thereby fully and rigorously incorporating the effects of double diffraction. A total of 79136 inorganic phases are included with original Crystal Data reference codes, allowing access to all the information in NIST Crystal Data. Specific examples illustrate the robustness of this approach. This database will be most useful to researchers in mineralogy, metallurgy, materials science, forensics and analytical chemistry who seek to identify well characterized phases with known unit cells.

Electron crystallography of zeolites. 3. Calcined MCM-22 and MCM-49, a case of subtle differences

2003 ◽  
Vol 218 (9) ◽  
Author(s):  
Douglas L. Dorset
Keyword(s):  
Electron Diffraction ◽  
Single Crystal ◽  
Crystal Structures ◽  
Direct Methods ◽  
Intensity Data ◽  
Electron Crystallography ◽  
Diffraction Intensity ◽  
Crystal Electron

AbstractSingle crystal electron diffraction intensity data, analyzed by direct methods for determining crystallographic phases, have been employed to seek differences between the crystal structures of calcined MCM-22 and MCM-49. A direct comparison of

Compositional variation within some sedimentary chlorites and some comments on their origin

1985 ◽  
Vol 49 (352) ◽  
pp. 375-386 ◽  
Author(s):  
C. D. Curtis ◽  
C. R. Hughes ◽  
J. A. Whiteman ◽  
C. K. Whittle
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Diffraction ◽  
Single Crystal ◽  
Compositional Variation ◽  
Analytical Transmission Electron Microscopy ◽  
Decomposition Reactions ◽  
Transmission Electron ◽  
Diffraction Patterns ◽  
Crystal Electron

AbstractA range of authigenic sedimentary chlorites from sandstones has been studied by analytical transmission electron microscopy. Selected area (single crystal) electron diffraction patterns are of the Ib (β = 90°) polytype confirming the earlier observations of Hayes (1970).TEM analyses show all samples to be relatively rich in both Al and Fe. In the general formula (Mg,Fe,Al)n [Si8−xAlxO20](OH)16, x varies between 1.5 and 2.6; Fe/(Fe + Mg) between 0.47 and 0.83 and n between 10.80 and 11.54. Octahedral Al is close to 3 in this formulation and Fe2+ predominates over Fe3+. Swelling chlorites have significantly different compositions which are consistent with smectite/chlorite interstratifications.The Ib (β = 90°) polytype appears to be stable under conditions of moderate to deep burial. It replaces berthierine and swelling chlorites formed at lower temperatures. As commonly seen in grain coatings, however, it precipitates from porewater; solutes probably being contributed from several mineral decomposition reactions.

The use of Direct Phasing Methods for Single Crystal Electron Diffraction Data. I. Methylene Subcells

1976 ◽  
Vol 34 ◽  
pp. 544-545
Author(s):  
D. L. Dorset ◽  
H. A. Hauptman
Keyword(s):  
Crystal Structure ◽  
Electron Diffraction ◽  
Diffraction Data ◽  
Crystal Structure Analysis ◽  
Electron Diffraction Data ◽  
Trial And Error ◽  
Mosaic Crystals ◽  
Crystal Electron ◽  
Kinematical Theory

The significant impediment to the use of electron diffraction data for crystal structure analysis is, of course, the perturbation of n-beam dynamical effects. In more severe cases this dynamical perturbation gives an intensity distribution in the diffraction pattern which is not directly related to the underlying crystal structure, thus making the determination of complex structures nearly impossible by this technique.However, as was experimentally established in Vainshtein's laboratory and is theoretically predicted, the diffraction of electrons from thin mosaic crystals composed of light atoms is in accord with kinematical theory to a good first approximation and, furthermore, ab initiocrystal structure analyses are tractable viastandard crystallographic phase determination. To date the few electronographic determinations of unknown organic structures have used either trial and error or Patterson techniques.

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