A Simple Vector Method for the Determination of Orientations of Cubic Single Crystals from Back Reflection X‐Ray Photographs

1944 ◽  
Vol 15 (8) ◽  
pp. 610-612 ◽  
Author(s):  
Beulah Field Decker
Keyword(s):  
Single Crystals ◽  
Vector Method ◽  
X Ray ◽  
Back Reflection

Lattice-constant and stress measurement in single crystals: a new method

2005 ◽  
Vol 38 (4) ◽  
pp. 678-684 ◽  
Author(s):  
Balder Ortner
Keyword(s):  
Single Crystal ◽  
Single Crystals ◽  
Lattice Constant ◽  
Stress Measurement ◽  
New Method ◽  
Lattice Plane ◽  
X Ray ◽  
Advantages And Disadvantages

A method for the X-ray determination of lattice-plane distances is given. Similar to Bond's method, it is based on the measurement of rocking curves, with some advantages and disadvantages compared with the former method. The new method is especially designed for single-crystal stress measurement. Its usefulness is demonstrated in two examples of lattice-constant and stress measurement.

scholarly journals Rubidium tetrafluoridobromate(III): redetermination of the crystal structure from single-crystal X-ray diffraction data

IUCrData ◽  
2019 ◽  
Vol 4 (11) ◽  
Author(s):  
Artem V. Malin ◽  
Sergei I. Ivlev ◽  
Roman V. Ostvald ◽  
Florian Kraus
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Single Crystals ◽  
Diffraction Data ◽  
Structure Type ◽  
X Ray Diffraction ◽  
X Ray ◽  
Square Planar ◽  
Atomic Coordinates

Single crystals of rubidium tetrafluoridobromate(III), RbBrF4, were grown by melting and recrystallizing RbBrF4 from its melt. This is the first determination of the crystal structure of RbBrF4 using single-crystal X-ray diffraction data. We confirmed that the structure contains square-planar [BrF4]− anions and rubidium cations that are coordinated by F atoms in a square-antiprismatic manner. The compound crystallizes in the KBrF4 structure type. Atomic coordinates and bond lengths and angles were determined with higher precision than in a previous report based on powder X-ray diffraction data [Ivlev et al. (2015). Z. Anorg. Allg. Chem. 641, 2593–2598].

A Systematic Method for Indexing Spots of Single Crystals in Laue X-Ray Photographs

1963 ◽  
Vol 7 ◽  
pp. 107-116
Author(s):  
Y. A. Konnan
Keyword(s):  
Single Crystal ◽  
Single Crystals ◽  
Crystal Structures ◽  
Trial And Error ◽  
Systematic Method ◽  
X Ray ◽  
Computer Methods ◽  
Cubic System ◽  
Complex Crystal

AbstractThe determination of the orientation of a single crystal by Laue X-ray photographs is dependent on the identification of the indices of the spots. At the present time, the determination of indices is done by various methods, none of which is entirely systematical. A method for establishing the indices of the spots which avoids a trial-and-error approach is described here. The method is graphical, uses a specially compiled table of erystallographic angles and is not dependent on the complexity of the structure of the crystal or its symmetry. An example of the cubic system is included. With more complex crystal structures the method becomes very laborious and the help of computer methods is suggested.

scholarly journals Determination of the Chemical Composition of Lithium Niobate Powders

Crystals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 340 ◽  
Author(s):  
Oswaldo Sánchez-Dena ◽  
Carlos J. Villagómez ◽  
César D. Fierro-Ruíz ◽  
Artemio S. Padilla-Robles ◽  
Rurik Farías ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Lithium Niobate ◽  
Single Crystals ◽  
Structure Refinement ◽  
Linear Equations ◽  
Powdered Material ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scattering Effects

Existent methods for determining the composition of lithium niobate single crystals are mainly based on their variations due to changes in their electronic structure, which accounts for the fact that most of these methods rely on experimental techniques using light as the probe. Nevertheless, these methods used for single crystals fail in accurately predicting the chemical composition of lithium niobate powders due to strong scattering effects and randomness. In this work, an innovative method for determining the chemical composition of lithium niobate powders, based mainly on the probing of secondary thermodynamic phases by X-ray diffraction analysis and structure refinement, is employed. Its validation is supported by the characterization of several samples synthesized by the standard and inexpensive method of mechanosynthesis. Furthermore, new linear equations are proposed to accurately describe and determine the chemical composition of this type of powdered material. The composition can now be determined by using any of four standard characterization techniques: X-Ray Diffraction (XRD), Raman Spectroscopy (RS), UV-vis Diffuse Reflectance (DR), and Differential Thermal Analysis (DTA). In the case of the existence of a previous equivalent description for single crystals, a brief analysis of the literature is made.

New Macrocyclic Ligands. XI. Synthesis, X-Ray Structure and Computational Studies of a New N2O4S2-Heteroatom Cage

2000 ◽  
Vol 53 (9) ◽  
pp. 799 ◽  
Author(s):  
Ian M. Atkinson ◽  
David C. R. Hockless ◽  
Leonard F. Lindoy ◽  
Owen A. Matthews ◽  
George V. Meehan ◽  
...  
Keyword(s):  
Single Crystals ◽  
Structure Determination ◽  
Macrocyclic Ligands ◽  
Computational Studies ◽  
Mo Calculations ◽  
X Ray ◽  
Semiempirical Mo Calculations ◽  
Cage Molecule ◽  
Helical Configuration

The synthesis and single-crystal X-ray structure determination of a new cage molecule containing four oxygen, two sulfur, and two nitrogen heteroatoms are described. The structure determination shows that a twist occurs about each (tribenzyl) nitrogen bridgehead so that an overall helical configuration within putative quasi-2 symmetry is generated; both nitrogens have their lone pairs orientatedexo. Single crystals of this compound are homochiral. Semiempirical MO calculations have been used to probe the topological rigidity of this system relative to the more symmetrical analogue incorporating six oxygen and two nitrogen heteroatoms reported previously. The introduction of the sulfur atoms appears to restrict the facile interconversion between enantiomers that was predicted for the N2O6-analogue mentioned above. The implications of the structure for the design of larger cages are discussed.

Orientation of Back Reflection Laue Photographs: A Semi-Automated Approach

1975 ◽  
Vol 19 ◽  
pp. 725-734 ◽  
Author(s):  
R. P. Goehner
Keyword(s):  
Computer Simulation ◽  
Single Crystals ◽  
Stereographic Projection ◽  
Crystallographic Plane ◽  
Polycrystalline Materials ◽  
Laue Pattern ◽  
X Ray ◽  
Lattice Constants ◽  
Stereographic Triangle ◽  
Back Reflection

Computer simulation of back reflection Laue patterns now provides the means to plot Laue patterns for any crystal system in any orientation. This capability makes it possible to determine, rapidly and accurately, the orientation of single crystals and large grains in polycrystalline materials even in cases where little or no symmetry is displayed in the Laue photograph. A set of standard Laue patterns is first simulated to cover the stereographic triangle of the crystal being studied. The Laue photograph obtained from the crystal, or grain, is compared with the set of simulated Laue patterns. The pattern most similar to the photograph is used to determine the (HKL) values of three Laue spots. The (HKL) values of these spots and half their angular separations from the x-ray beam, along with the lattice constants, are used by a computer program to calculate the (HKL) value of the crystallographic plane perpendicular to the x-ray beam. A simulated Laue pattern can now be obtained in exactly the same orientation and it can be drawn directly to the scale of the Laue photograph. Thus the validity of the orientation can be easily verified by direct comparison. The (HKL) value of the crystallographic plane perpendicular to the x-ray beam can also be used to plot a stereographic projection of the crystal poles. Therefore, the complete orientation of the crystal can be determined.

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