The determination of the cation distribution in olivine from single crystal Mössbauer studies

1973 ◽  
Vol 26 (2) ◽  
pp. 231 ◽  
Author(s):  
JF Duncan ◽  
JH Johnston
Keyword(s):  
Single Crystal ◽  
Single Crystals ◽  
Absorption Spectra ◽  
Cation Distribution ◽  
Quadrupole Split ◽  
Mössbauer Studies ◽  
Peak Areas

Mossbauer absorption spectra of different orientations of single crystals of olivine (MgFe)2SiO4 have been determined. The variation of the ratio of peak areas of the quadrupole split lines has allowed the M(1) and M(2) site positions of the Fe2+ ions to be identified, and has shown that the Fe2+ ions are evenly distributed between these sites.

Two lithium tricyanomethanide compounds: syntheses and single-crystal structure determination of LiK[C(CN)3]2 and Li[C(CN)3]·½ (H3C)2CO

2015 ◽  
Vol 70 (3) ◽  
pp. 191-196 ◽  
Author(s):  
Olaf Reckeweg ◽  
Francis J. DiSalvo
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Single Crystals ◽  
Structure Determination ◽  
Monoclinic Space Group ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
Cell Parameters ◽  
New Compounds

AbstractThe new compounds LiK[C(CN)3]2 and Li[C(CN)3]·½ (H3C)2CO were synthesized and their crystal structures were determined. Li[C(CN)3]·½ (H3C)2CO crystallizes in the orthorhombic space group Ima2 (no. 46) with the cell parameters a=794.97(14), b=1165.1(2) and c=1485.4(3) pm, while LiK[C(CN)3]2 adopts the monoclinic space group P21/c (no. 14) with the cell parameters a=1265.7(2), b=1068.0(2) and c=778.36(12) pm and the angle β=95.775(7)°. Single crystals of K[C(CN)3] were also acquired, and the crystal structure was refined more precisely than before corroborating earlier results.

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].

Characteristic Investigations of Stoichiometric LiNbO3 Single Crystal Fiber Co-Doped with Tb and Mn

2004 ◽  
Vol 449-452 ◽  
pp. 985-988
Author(s):  
S.M. Lee ◽  
J.W. Shur ◽  
T.I. Shin ◽  
W.S. Yang ◽  
G.Y. Kim ◽  
...  
Keyword(s):  
Absorption Band ◽  
Single Crystal ◽  
Optical Microscopy ◽  
Single Crystals ◽  
Absorption Spectra ◽  
Room Temperature ◽  
Crystal Fiber ◽  
Ft Ir ◽  
Homogeneous Distributions ◽  
Co Doped

[MnO2(1.0mol%) : Tb4O7(0.5mo%)] doped stoichiometric LiNbO3 (Mn:Tb:SLN) single crystals of 0.5~1.0 mm in diameter and 30~35 mm in length were grown by micro pulling down(µ-PD) method. We investigated the photoluminescence (PL) properties of Mn:Tb:SLN single crystal. The OH- absorption band of the single crystals observed infrared the absorption spectra by using an FT-IR spectrophotometer at room temperature. Homogeneous distributions of Mn and Tb concentration were confirmed by the EPMA and observed defects by optical microscopy.

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.

Measurements of Quadrupole Interactions by Nuclear Orientation and Quadrupole-Interaction-Resolved NMR on Oriented Nuclei

1986 ◽  
Vol 41 (1-2) ◽  
pp. 95-98 ◽  
Author(s):  
K.-H. Ebeling ◽  
R. Eder ◽  
E. Hagn ◽  
E. Zech ◽  
M. Deicher
Keyword(s):  
Electric Field ◽  
Single Crystal ◽  
Electric Field Gradient ◽  
Single Crystals ◽  
Quadrupole Interaction ◽  
Nuclear Orientation ◽  
Hyperfine Fields ◽  
Host Matrix ◽  
Quadrupole Interactions

The techniques of quadrupole-interaction nuclear-orientation and quadrupole-interaction-resolvedNMR on oriented nuclei were applied to radioactive 111In (T1/2 = 2.8 d), 198Au(T1/2= 2.7 d) and 199Au (T1/2 = 3.1 d), mass-separator-implanted into single crystals of hep Coand hep Gd. For 111InGd the quadrupole interaction was observed via the broadening of theresonance and the dependence of the effective quadrupole interaction on the angle θbetween thec-axis of the single crystal and the direction of magnetization. For 198AuGd the large electric fieldgradient known from the literature could not be confirmed. For 198AuCo and 199AuCo thequadrupole substructure has been resolved, and the electric field gradient of Au in hep Co was determined to be -0.84(4) x 1017V/cm2. The magnetic hyperfine fields of Au in hep and fee Codiffer by about 20%. These experiments have shown that hep Co may be a good host matrix forthe determination of the quadrupole interaction of heavy radioactive nuclei with resonanceprecision.

scholarly journals First determination of dissolution rates of oriented UO2 single crystals

MRS Advances ◽  
2020 ◽  
Vol 5 (1-2) ◽  
pp. 19-26
Author(s):  
S. BERTOLOTTO ◽  
S. SZENKNECT ◽  
S. LALLEMAN ◽  
R. PODOR ◽  
L. CLAPAREDE ◽  
...  
Keyword(s):  
Nitric Acid ◽  
Single Crystal ◽  
Single Crystals ◽  
Crystallographic Orientation ◽  
Room Temperature ◽  
Second Step ◽  
Atomic Composition ◽  
Acid Media ◽  
Fluorite Type

Abstract:Millimetre UO2 single crystals were cut and oriented at JRC Karlsruhe. The orientation of each face of the parallelepiped single crystals was determined with Laue diffraction and the corresponding surface area by geometric measurements. Then, the (111), (100), (110) faces of each single crystal were polished to optical grade and characterized by XRD in order to confirm the surface orientation. The dissolution of the three single crystals was achieved in nitric acid media under dynamic conditions, at room temperature. Two dissolution regimes were observed for all samples. The normalized dissolution rate measured in the first step was not influenced by the crystallographic orientation of the faces. However, during the second step, (110) oriented faces were found to dissolve 4 times faster than the (100) faces. One explanation could involve the atomic composition of each oriented surface in the fluorite-type structure

Single-crystal 57Fe Mössbauer studies of the site positions in cordierite

1974 ◽  
Vol 27 (2) ◽  
pp. 249 ◽  
Author(s):  
JF Duncun ◽  
JH Johnson
Keyword(s):  
Electric Field ◽  
Total Iron ◽  
Total Iron Content ◽  
Electric Field Gradients ◽  
Quadrupole Split ◽  
Octahedral Sites ◽  
Field Gradients ◽  
Tetrahedral Sites ◽  
Peak Areas

Mossbauer (57Fe) absorption spectra of different orientations of single crystals of cordierite (Mg,Fe)2AI3 [Si5AIO18] have been determined. The variation of the ratio of the peak areas of the quadrupole split lines with orientation has enabled the determination of the electric field gradient directions, and the site positions and occupancies of the Fe2+ and Fe3+ ions. Of a total iron content of 1.85% w/w, 79% is present as Fe2+ replacing Mg2+ in the octahedral sites; 19% as Fe2+ occupying the larger of two channel sites; and 1% as Fe3+ replacing Al3+ in the larger of the two tetrahedral sites. A possible interpretation of the observed pleochroism in terms of Fe2+-Fe2+ and Fe2+-Fe3+ electranic interactions along the directions of the electric field gradients of these ions is suggested.

Sign and Orientation Determination of the Principal Axis of the Electric Field Gradient in Fe57 Enriched Deoxygenated Myoglobin Single Crystals

1974 ◽  
Vol 29 (3-4) ◽  
pp. 241-244 ◽  
Author(s):  
Ulrich Gonser ◽  
Yutaka Maeda ◽  
Alfred Trautwein ◽  
Fritz Parak ◽  
Helmut Formanek
Keyword(s):  
Electric Field ◽  
Electric Field Gradient ◽  
Single Crystals ◽  
Field Gradient ◽  
Principal Axis ◽  
Quadrupole Split ◽  
Mössbauer Measurements ◽  
Orientation Determination ◽  
Two Alternatives

Single crystals of myoglobin enriched on Fe57 with a diameter of about 0.5 mm were prepared. After deoxygenation crystallographic alignment and Mössbauer measurements were carried out at 77°K. In the experiment eight different orientations were selected by rotating the crystal around the b axis, thus, b axis and γ-ray propagation direction remained perpendicular to each other. From the intensity ratio of the quadrupole split spectra we derive the sign and the orientation of the principal axis of the electric field gradient. We find Vzz to be positive and forming an angle of 40° to the b axis. From two alternatives consistent with our experiments we conclude that VZZ is most likely oriented along one of the four Fe-N directions in the heme.

Sign in / Sign up

Export Citation Format

Share Document