X-ray diffraction study for one-dimensional ionic conductors K x (Ga1 − y Aly)2 + x Ti2 − x O7 (x ≃ 0.14, y ≃ 0.10, 0.23, 0.39)

2005 ◽  
Vol 61 (6) ◽  
pp. 608-615
Author(s):  
Yuichi Michiue ◽  
Shinzo Yoshikado
Keyword(s):  
Atomic Displacement ◽  
Ionic Conductors ◽  
X Ray Diffraction ◽  
Conduction Path ◽  
Coordination Polyhedra ◽  
Bottleneck Effect ◽  
One Dimensional ◽  
X Ray ◽  
Al Content ◽  
Atomic Displacement Parameters

The structures of one-dimensional ionic conductors K x (Ga1 − y Al y )2 + x Ti2 − x O7 (x ≃ 0.14, y ≃ 0.10, 0.23, 0.39) were refined by single-crystal X-ray diffraction. A one-dimensional tunnel-like space with a large cross section is formed by the linkage of coordination polyhedra of the metal and oxygen ions; K ions are distributed in the tunnel. Significant differences were seen in structures with different Al content; these differences could be explained by considerations in crystal chemistry. The probability density functions (PDFs) of the K ion were obtained using up to fourth-order terms of the atomic displacement parameters. The joint PDFs for the K ion have clarified that a K conduction path deviates slightly from the central axis of the tunnel in all the samples. In contrast with the usual one-dimensional ionic conductors, no distinct bottleneck effect was observed from the joint-PDFs and one-particle potentials.

Probability density analyses of guest ions in hollandite Ax Mg x/2Ti8 − x/2O16 (A = K, Rb)

2007 ◽  
Vol 63 (4) ◽  
pp. 577-583 ◽  
Author(s):  
Yuichi Michiue
Keyword(s):  
Probability Density ◽  
Atomic Displacement ◽  
Structure Model ◽  
Ionic Conductors ◽  
X Ray Diffraction ◽  
One Dimensional ◽  
Conventional Structure ◽  
Atomic Displacement Parameters ◽  
Process Energy ◽  
Mobile Ions

Probability density functions (PDFs) of mobile ions in one-dimensional ionic conductors of hollandite A x Mg x/2Ti8 − x/2O16 (A = K, Rb) were examined by single-crystal X-ray diffraction. A conventional structure model was modified by imposing an additional constraint condition, which is based on microscopic description for the possible displacement of mobile ions adjacent to a vacancy in the tunnel. Joint PDFs and one-particle potentials for mobile ions were obtained from the structure models applying harmonic and anharmonic atomic displacement parameters (ADPs). Potential curves of the ion hopping between neighboring cavities were calculated from the joint PDF of the specific ions of the process. Energy barriers of the ion hopping were estimated at 52–60 meV from anharmonic ADP models of K-hollandite, while the values varied from 140 to 250 meV for Rb-hollandite.

scholarly journals Crystal Structure of Moganite and Its Anisotropic Atomic Displacement Parameters Determined by Synchrotron X-ray Diffraction and X-ray/Neutron Pair Distribution Function Analyses

Minerals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 272
Author(s):  
Seungyeol Lee ◽  
Huifang Xu ◽  
Hongwu Xu ◽  
Joerg Neuefeind
Keyword(s):  
Crystal Structure ◽  
Distribution Function ◽  
Single Crystal ◽  
Pair Distribution Function ◽  
Atomic Displacement ◽  
Single Crystal Xrd ◽  
X Ray Diffraction ◽  
X Ray ◽  
Neutron Pair ◽  
Atomic Displacement Parameters

The crystal structure of moganite from the Mogán formation on Gran Canaria has been re-investigated using high-resolution synchrotron X-ray diffraction (XRD) and X-ray/neutron pair distribution function (PDF) analyses. Our study for the first time reports the anisotropic atomic displacement parameters (ADPs) of a natural moganite. Rietveld analysis of synchrotron XRD data determined the crystal structure of moganite with the space group I2/a. The refined unit-cell parameters are a = 8.7363(8), b = 4.8688(5), c = 10.7203(9) Å, and β = 90.212(4)°. The ADPs of Si and O in moganite were obtained from X-ray and neutron PDF analyses. The shapes and orientations of the anisotropic ellipsoids determined from X-ray and neutron measurements are similar. The anisotropic ellipsoids for O extend along planes perpendicular to the Si-Si axis of corner-sharing SiO4 tetrahedra, suggesting precession-like movement. Neutron PDF result confirms the occurrence of OH over some of the tetrahedral sites. We postulate that moganite nanomineral is stable with respect to quartz in hypersaline water. The ADPs of moganite show a similar trend as those of quartz determined by single-crystal XRD. In short, the combined methods can provide high-quality structural parameters of moganite nanomineral, including its ADPs and extra OH position at the surface. This approach can be used as an alternative means for solving the structures of crystals that are not large enough for single-crystal XRD measurements, such as fine-grained and nanocrystalline minerals formed in various geological environments.

scholarly journals Single-crystal neutron and X-ray diffraction study of garnet-type solid-state electrolyte Li6La3ZrTaO12: an in situ temperature-dependence investigation (2.5 ≤ T ≤ 873 K)

2021 ◽  
Vol 77 (1) ◽  
pp. 123-130
Author(s):  
Günther J. Redhammer ◽  
Martin Meven ◽  
Steffen Ganschow ◽  
Gerold Tippelt ◽  
Daniel Rettenwander
Keyword(s):  
Solid State ◽  
Single Crystal ◽  
Czochralski Method ◽  
Atomic Displacement ◽  
X Ray Diffraction ◽  
Solid State Electrolyte ◽  
Cubic Symmetry ◽  
X Ray ◽  
Site Occupation ◽  
Atomic Displacement Parameters

Large single crystals of garnet-type Li6La3ZrTaO12 (LLZTO) were grown by the Czochralski method and analysed using neutron diffraction between 2.5 and 873 K in order to fully characterize the Li atom distribution, and possible Li ion mobility in this class of potential candidates for solid-state electrolyte battery material. LLZTO retains its cubic symmetry (space group Ia 3 d) over the complete temperature range. When compared to other sites, the octahedral sites behave as the most rigid unit and show the smallest increase in atomic displacement parameters and bond length. The La and Li sites show similar thermal expansion in their bond lengths with temperature, and the anisotropic and equivalent atomic displacement parameters exhibit a distinctly larger increase at temperatures above 400 K. Detailed inspection of nuclear densities at the Li1 site reveal a small but significant displacement from the 24d position to the typical 96h position, which cannot, however, be resolved from the single-crystal X-ray diffraction data. The site occupation of LiI ions on Li1 and Li2 sites remains constant, so there is no change in site occupation with temperature.

scholarly journals Room-temperature ultrahigh-resolution time-of-flight neutron and X-ray diffraction studies of H/D-exchanged crambin

2012 ◽  
Vol 68 (2) ◽  
pp. 119-123 ◽  
Author(s):  
Julian C.-H. Chen ◽  
Zoë Fisher ◽  
Andrey Y. Kovalevsky ◽  
Marat Mustyakimov ◽  
B. Leif Hanson ◽  
...  
Keyword(s):  
Neutron Diffraction ◽  
Room Temperature ◽  
Protein Structures ◽  
Atomic Displacement ◽  
Protein Crystal ◽  
X Ray Diffraction ◽  
Resolution Time ◽  
X Ray ◽  
Two Temperatures ◽  
Atomic Displacement Parameters

The room-temperature (RT) X-ray structure of H/D-exchanged crambin is reported at 0.85 Å resolution. As one of the very few proteins refined with anisotropic atomic displacement parameters at two temperatures, the dynamics of atoms in the RT and 100 K structures are compared. Neutron diffraction data from an H/D-exchanged crambin crystal collected at the Protein Crystallography Station (PCS) showed diffraction beyond 1.1 Å resolution. This is the highest resolution neutron diffraction reported to date for a protein crystal and will reveal important details of the anisotropic motions of H and D atoms in protein structures.

Undistorted linear Bi chains with hypervalent bonding in La3TiBi5 from single-crystal X-ray diffraction

2018 ◽  
Vol 74 (5) ◽  
pp. 618-622 ◽  
Author(s):  
Alexander Ovchinnikov ◽  
Svilen Bobev
Keyword(s):  
Electronic Structure ◽  
Single Crystal ◽  
Three Dimensional ◽  
Atomic Displacement ◽  
X Ray Diffraction ◽  
One Dimensional ◽  
X Ray ◽  
Orbital Mixing ◽  
The Stability ◽  
Structure Calculations

The crystal structure of the lanthanum titanium bismuthide La3TiBi5 (Pearson code hP18, Wyckoff sequence b d g2) has been established from single-crystal X-ray diffraction data and analyzed in detail using first-principles calculations. There are no anomalies pertaining to the atomic displacement parameter of the Ti site, previously reported based on a powder X-ray diffraction analysis of this compound. The anionic substructure contains columns of face-sharing TiBi6 octahedra and linear Bi chains. Due to a significant La(5d) and Bi(6p) orbital mixing, a perfectly one-dimensional character of the Bi chains is not realised, while a three-dimensional electronic structure is established instead. The latter fact explains the stability of the polyanionic pnictide units against Peierls distortions. The hypervalent bonding in the Bi chains is reflected in a rather long Bi—Bi distance of 3.2264 (4) Å and a typical pattern of bonding and antibonding interactions, as revealed by electronic structure calculations.

Electron density and electrostatic potential of KNiF3: multipole, orbital and topological analyses of vacuum-camera-imaging plate and four-circle diffractometer data

1999 ◽  
Vol 55 (6) ◽  
pp. 923-930 ◽  
Author(s):  
Yury Ivanov ◽  
Elizabeth A. Zhurova ◽  
Vladimir V. Zhurov ◽  
Kiyoaki Tanaka ◽  
Vladimir Tsirelson
Keyword(s):  
Electron Density ◽  
Electrostatic Potential ◽  
Atomic Displacement ◽  
Imaging Plate ◽  
X Ray Diffraction ◽  
X Ray ◽  
Camera Imaging ◽  
Model Treatment ◽  
Atomic Displacement Parameters ◽  
Good Agreement

The electron density and electrostatic potential of KNiF3, nickel potassium trifluoride, were studied using multipole and orbital model treatment of the precision X-ray diffraction data measured by vacuum-camera-imaging plate and four-circle diffractometer methods. Different experimental methods lead to similar multipole and atomic displacement parameters and to qualitatively the same electron densities. Good agreement was also achieved for the Laplacians of the electron density and the electrostatic potentials. Some pitfalls of the vacuum-camera-imaging plate method that could be improved are discussed.

Crystal structure and structural phase transition in bismuth-containing HoFe3(BO3)4 in the temperature range 11–500 K

2019 ◽  
Vol 75 (6) ◽  
pp. 954-968 ◽  
Author(s):  
Ekaterina S. Smirnova ◽  
Olga A. Alekseeva ◽  
Alexander P. Dudka ◽  
Dmitry N. Khmelenin ◽  
Kirill V. Frolov ◽  
...  
Keyword(s):  
Phase Transition ◽  
Structural Phase Transition ◽  
Structural Phase ◽  
Local Environment ◽  
Atomic Displacement ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Atomic Displacement Parameters ◽  
Thermal Vibrations

An accurate single-crystal X-ray diffraction study of bismuth-containing HoFe3(BO3)4 between 11 and 500 K has revealed structural phase transition at T str = 365 K. The Bi atoms enter the composition from Bi2Mo3O12-based flux during crystal growth and significantly affect T str. The content of Bi was estimated by two independent methods, establishing the composition as (Ho0.96Bi0.04)Fe3(BO3)4. In the low-temperature (LT) phase below T str the (Ho0.96Bi0.04)Fe3(BO3)4 crystal symmetry is trigonal, of space group P3121, whereas at high temperature (HT) above 365 K the symmetry increases to space group R32. There is a sharp jump of oxygen O1 (LT) and O2 (LT) atomic displacement parameters (ADP) at T str. O1 and O2 ADP ellipsoids are the most elongated over 90–500 K. In space group R32 specific distances decrease steadily or do not change with decreasing temperature. In space group P3121 the distortion of the polyhedra Ho(Bi)O6, Fe1O6 and Fe2O6, B2O3 and B3O3 increases with decreasing temperature, whereas the triangles B1O3 remain almost equilateral. All BO3 triangles deviate from the ab plane with decreasing temperature. Fe–Fe distances in Fe1 chains decrease, while distances in Fe2 chains increase with decreasing temperature. The Mössbauer study confirms that the FeO6 octahedra undergo complex dynamic distortions. However, all observed distortions are rather small, and the general change in symmetry during the structural phase transition has very little influence on the local environment of iron in oxygen octahedra. The Mössbauer spectra do not distinguish two structurally different Fe1 and Fe2 positions in the LT phase. The characteristic temperatures of cation thermal vibrations were calculated using X-ray diffraction and Mössbauer data.

N—H...O and C—H...F hydrogen bonds in the incommensurately modulated crystal structure of adamantan-1-ammonium 4-fluorobenzoate

2014 ◽  
Vol 70 (4) ◽  
pp. 652-659 ◽  
Author(s):  
Andreas Schönleber ◽  
Sander van Smaalen ◽  
Hans-Christoph Weiss ◽  
Andreas J. Kesel
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Diffraction Data ◽  
Low Temperatures ◽  
Atomic Displacement ◽  
Organic Salt ◽  
X Ray Diffraction ◽  
X Ray ◽  
Molecular Cations ◽  
Atomic Displacement Parameters

At low temperatures the organic salt adamantan-1-ammonium 4-fluorobenzoate, C10H18N+·C7H4FO2−, possesses an incommensurately modulated crystal structure. The effect of the modulation on the atomic arrangement and intermolecular interactions is studied by analysing single-crystal X-ray diffraction data within the (3 + 1)-dimensional superspace approach and superspace groupP21/n(α0γ)00. The modulation strongly affects the position of the atoms as well as their atomic displacement parameters. Nevertheless, the molecular cations and anions are built by rigid moieties, which vary their orientation with respect to each other as a function of the phase of the modulationt. Cations and anions are connected into slabs by dense N—H...O and C—H...F hydrogen-bonded networks, which are characterized by being rather rigid and which show only a little variation as a function of the phase of the modulationt.

scholarly journals Redetermination of the crystal structure of R 5Si4 (R = Pr, Nd) from single-crystal X-ray diffraction data

2020 ◽  
Vol 76 (4) ◽  
pp. 510-513
Author(s):  
Kaori Yokota ◽  
Ryuta Watanuki ◽  
Miki Nakashima ◽  
Masatomo Uehara ◽  
Jun Gouchi ◽  
...  
Keyword(s):  
Single Crystal ◽  
Diffraction Data ◽  
Three Dimensional ◽  
Atomic Displacement ◽  
Crystal Data ◽  
X Ray Diffraction ◽  
Acta Cryst ◽  
X Ray ◽  
Atomic Displacement Parameters ◽  
First Time

The crystal structures of praseodymium silicide (5/4), Pr5Si4, and neodymium silicide (5/4), Nd5Si4, were redetermined using high-quality single-crystal X-ray diffraction data. The previous structure reports of Pr5Si4 were only based on powder X-ray diffraction data [Smith et al. (1967). Acta Cryst. 22 940–943; Yang et al. (2002b). J. Alloys Compd. 339, 189–194; Yang et al., (2003). J. Alloys Compd. 263, 146–153]. On the other hand, the structure of Nd5Si4 has been determined from powder data [neutron; Cadogan et al., (2002). J. Phys. Condens. Matter, 14, 7191–7200] and X-ray [Smith et al. (1967). Acta Cryst. 22 940–943; Yang et al. (2002b). J. Alloys Compd. 339, 189–194; Yang et al., (2003). J. Alloys Compd. 263, 146–153] and single-crystal data with isotropic atomic displacement parameters [Roger et al., (2006). J. Alloys Compd. 415, 73–84]. In addition, the anisotropic atomic displacement parameters for all atomic sites have been determined for the first time. These compounds are confirmed to have the tetragonal Zr5Si4-type structure (space group: P41212), as reported previously (Smith et al., 1967). The structure is built up by distorted body-centered cubes consisting of Pr(Nd) atoms, which are linked to each other by edge-sharing to form a three-dimensional framework. This framework delimits zigzag channels in which the silicon dimers are situated.

Sign in / Sign up

Export Citation Format

Share Document