Local Structure of Molten CdCl2 Systems

2004 ◽  
Vol 59 (11) ◽  
pp. 819-824 ◽  
Author(s):  
Y. Okamoto ◽  
H. Shiwaku ◽  
T. Yaita ◽  
S. Suzuki ◽  
K. Minato ◽  
...  
Keyword(s):  
Fine Structure ◽  
Solid State ◽  
Local Structure ◽  
Room Temperature ◽  
Structural Parameters ◽  
Molten State ◽  
Tetrahedral Coordination ◽  
X Ray Diffraction ◽  
X Ray ◽  
X Ray Absorption

The local structure of molten CdCl2 was investigated by X-ray absorption fine structure (XAFS) and X-ray diffraction(XRD) analyses. The nearest Cd2+-Cl− distance decreases from 2.61 Å in the room temperature solid state to 2.47 - 2.50 Å in the molten state. The coordination number decreases from 6 in the solid to 4 in the melt. The obtained structural parameters from the XAFS and the XRD analyses suggest that a tetrahedral coordination (CdCl4)2− is predominant in molten CdCl2. The XAFS result of a molten 50%CdCl2-KCl mixture shows that the 4-fold (CdCl4)2− structure holds also in the mixture

The Local Structure of Molten CdBr2

2005 ◽  
Vol 60 (1-2) ◽  
pp. 81-84
Author(s):  
Hideaki Shiwakua ◽  
Yoshihiro Okamoto ◽  
Tsuyashi Yaita ◽  
Shinichi Suzuki ◽  
Kazuo Minato ◽  
...  
Keyword(s):  
Fine Structure ◽  
High Temperature ◽  
Local Structure ◽  
Molten Salts ◽  
Room Temperature ◽  
Nearest Neighbor ◽  
Structural Parameters ◽  
Molten State ◽  
X Ray ◽  
X Ray Absorption

The local structure of molten CdBr2 was investigated by high temperature X-ray absorption fine structure (XAFS) analysis. The quartz cell designed for hygroscopic high temperature molten salts was successfully used in the measurement. At room temperature the nearest neighbor Cd2+-Br− distance decreased from 2.71 Å in solid state to 2.60 Å in the molten state. The coordination number decreased from 6 to 4 on melting. The obtained structural parameters showed that (CdBr4)2− is predominant in molten CdBr2.

scholarly journals Solid-state motion of OTeF5− compounds: detection by 19F NMR and IR spectroscopy and correlation with the X-ray structure of an orthorhombic crystalline modification of [C14H19N2+][OTeF5−] (C14H19N2+ = protonated 1,8-bis(dimethylamino)naphthalene)

1989 ◽  
Vol 67 (11) ◽  
pp. 2023-2029 ◽  
Author(s):  
Patti J. Kellett ◽  
Oren P. Anderson ◽  
Steven H. Strauss ◽  
Kent D. Abney
Keyword(s):  
Solid State ◽  
Nmr Spectra ◽  
Room Temperature ◽  
Variable Temperature ◽  
Structural Parameters ◽  
Crystalline Modification ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
X Ray ◽  
Triclinic Modification

An orthorhombic crystalline modification of [(PS)H+][OTeF5−] was studied by single crystal X-ray diffraction ((PS)H+ = protonated 1,8-bis(dimethylamino)naphthalene): orthorhombic, space group Cmcm, a = 8.607(2), b = 14.048(3), c = 13.365(2) Å, Z = 4, T = −130 °C. The structural parameters for the anion and cation in this modification (Mod-B) are very similar to those for the previously reported triclinic modification of this salt (Mod-A). However, variable temperature IR spectra for Mod-B suggest that the OTeF5− anion is exhibiting a two-site O/Fax interchange above −70 °C. Solid-state 19F NMR spectra suggest that this interchange may be as rapid as 104–105 s−1 at room temperature. Keywords: crystal structure of protonated 1,8-bis(dimethylamino)naphthalene)pentafluorotellurate(VI), polymorphism, solid state 19FNMR.

Local structure around Mn atoms in room-temperature ferromagnetic (In,Mn)As thin films probed by extended x-ray absorption fine structure

2004 ◽  
Vol 84 (4) ◽  
pp. 481-483 ◽  
Author(s):  
Y. L. Soo ◽  
S. Kim ◽  
Y. H. Kao ◽  
A. J. Blattner ◽  
B. W. Wessels ◽  
...  
Keyword(s):  
Thin Films ◽  
Fine Structure ◽  
Local Structure ◽  
Room Temperature ◽  
X Ray ◽  
Absorption Fine ◽  
X Ray Absorption

scholarly journals Local Structure and Dynamics of Functional Materials Studied by X-ray Absorption Fine Structure

Symmetry ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1315
Author(s):  
Takafumi Miyanaga
Keyword(s):  
Fine Structure ◽  
Local Structure ◽  
Chemical Reactivity ◽  
Functional Materials ◽  
X Ray ◽  
Structure And Dynamics ◽  
Absorption Fine ◽  
Structure Phase Transition ◽  
Local Electronic Structure ◽  
X Ray Absorption

X-ray absorption fine structure (XAFS) is a powerful technique used to analyze a local electronic structure, local atomic structure, and structural dynamics. In this review, I present examples of XAFS that apply to the local structure and dynamics of functional materials: (1) structure phase transition in perovskite PbTiO3 and magnetic FeRhPd alloys; (2) nano-scaled fluctuations related to their magnetic properties in Ni–Mn alloys and Fe/Cr thin films; and (3) the Debye–Waller factors related to the chemical reactivity for catalysis in polyanions and ligand exchange reaction. This study shows that the local structure and dynamics are related to the characteristic function of the materials.

Local atomic structure in tetragonal pure ZrO2nanopowders

2010 ◽  
Vol 43 (2) ◽  
pp. 227-236 ◽  
Author(s):  
Leandro M. Acuña ◽  
Diego G. Lamas ◽  
Rodolfo O. Fuentes ◽  
Ismael O. Fábregas ◽  
Márcia C. A. Fantini ◽  
...  
Keyword(s):  
Tetragonal Phase ◽  
Local Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Atomic Structures ◽  
Crystallite Sizes ◽  
Exafs Study ◽  
The Difference ◽  
X Ray Absorption ◽  
Good Agreement

The local atomic structures around the Zr atom of pure (undoped) ZrO2nanopowders with different average crystallite sizes, ranging from 7 to 40 nm, have been investigated. The nanopowders were synthesized by different wet-chemical routes, but all exhibit the high-temperature tetragonal phase stabilized at room temperature, as established by synchrotron radiation X-ray diffraction. The extended X-ray absorption fine structure (EXAFS) technique was applied to analyze the local structure around the Zr atoms. Several authors have studied this system using the EXAFS technique without obtaining a good agreement between crystallographic and EXAFS data. In this work, it is shown that the local structure of ZrO2nanopowders can be described by a model consisting of two oxygen subshells (4 + 4 atoms) with different Zr—O distances, in agreement with those independently determined by X-ray diffraction. However, the EXAFS study shows that the second oxygen subshell exhibits a Debye–Waller (DW) parameter much higher than that of the first oxygen subshell, a result that cannot be explained by the crystallographic model accepted for the tetragonal phase of zirconia-based materials. However, as proposed by other authors, the difference in the DW parameters between the two oxygen subshells around the Zr atoms can be explained by the existence of oxygen displacements perpendicular to thezdirection; these mainly affect the second oxygen subshell because of the directional character of the EXAFS DW parameter, in contradiction to the crystallographic value. It is also established that this model is similar to another model having three oxygen subshells, with a 4 + 2 + 2 distribution of atoms, with only one DW parameter for all oxygen subshells. Both models are in good agreement with the crystal structure determined by X-ray diffraction experiments.

Extended X-ray Absorption Fine Structure Studies of GaN Epilayers Doped in situ with Er and Eu During Molecular Beam Epitaxy

2003 ◽  
Vol 798 ◽  
Author(s):  
V. Katchkanov ◽  
J. F. W. Mosselmans ◽  
S. Dalmasso ◽  
K. P. O'Donnell ◽  
R. W. Martin ◽  
...  
Keyword(s):  
Fine Structure ◽  
Rare Earth ◽  
Molecular Beam Epitaxy ◽  
Local Structure ◽  
Molecular Beam ◽  
X Ray ◽  
Absorption Fine ◽  
X Ray Absorption ◽  
The Eu

ABSTRACTThe local structure around Er and Eu atoms introduced into GaN epilayers was studied by means of Extended X-ray Absorption Fine Structure above the appropriate rare-earth X-ray absorption edge. The samples were doped in situ during growth by Molecular Beam Epitaxy. The formation of ErN clusters was found in samples with high average Er concentrations of 32±6% and 12.4±0.8%, estimated by Wavelength Dispersive X-ray analysis. When the average Er concentration is decreased to 6.0±0.2%, 1.6±0.2% and 0.17±0.02%, Er is found in localised clusters of ErGaN phase with high local Er content. Similar behaviour is observed for Eu-doped samples. For an average Eu concentration of 30.5±0.5% clusters of pure EuN occur. Decreasing the Eu concentration to 10.4±0.5% leads to EuGaN clusters with high local Eu content. However, for a sample with an Eu concentration of 14.2±0.5% clustering of Eu was not observed.

scholarly journals Near edge x-ray absorption fine structure studies of local structure of dihexyldisulfide multilayer

2005 ◽  
Vol 54 (12) ◽  
pp. 5837
Author(s):  
Wu Tai-Quan ◽  
Tang Jing-Chang ◽  
Zhu Ping ◽  
Li Hai-Yang
Keyword(s):  
Fine Structure ◽  
Local Structure ◽  
X Ray ◽  
Absorption Fine ◽  
X Ray Absorption
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