The crystal structure of Zr2NiD4.5

2006 ◽  
Vol 62 (6) ◽  
pp. 972-978 ◽  
Author(s):  
M. H. Sørby ◽  
A. E. Gunnæs ◽  
O. M. Løvvik ◽  
H. W. Brinks ◽  
H. Fjellvåg ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Neutron Diffraction Data ◽  
X Ray Diffraction ◽  
Functional Theory ◽  
X Ray ◽  
Tetrahedral Sites ◽  
Powder Neutron Diffraction ◽  
Powder Neutron Diffraction Data

The crystal structure of Zr2NiD4.5 has been determined by a combination of synchrotron radiation powder X-ray diffraction, electron diffraction and powder neutron diffraction data. Deuterium ordering results in a triclinic supercell given by a super = 6.81560 (7), b super = 8.85137 (9), c super = 8.88007 (10) Å, αsuper = 79.8337 (8), βsuper = 90.0987 (9), γsuper = 90.3634 (9)°, which relates to the non-super unit cell as a super = −a, b super = −b − c, c super = −b + c. The centrosymmetric and fully ordered deuterium sublattice was determined by simulated annealing and Rietveld refinement. Deuterium was found to occupy three types of tetrahedral sites: two that are coordinated by four Zr atoms and one that is coordinated by three Zr atoms and one Ni atom. All D—D distances are longer than 2 Å. The feasibility of the crystal structure was supported by density functional theory calculations.

Crystal Structure of Cs2Zn(NO2)4: Influence of Steric Crowding on Nitrite Coordination

2005 ◽  
Vol 58 (3) ◽  
pp. 224 ◽  
Author(s):  
Susan G. Oates ◽  
Michael A. Hitchman ◽  
Brian W. Skelton ◽  
Robert Stranger ◽  
Horst Stratemeier ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Energy Curve ◽  
X Ray Diffraction ◽  
Nitrite Ion ◽  
Ligand Interaction ◽  
Functional Theory ◽  
X Ray ◽  
Steric Crowding

The crystal structure of Cs2[Zn(NO2)4] has been determined by X-ray diffraction. Each nitrite ion in the Zn(NO2)42− group forms one short [2.080(3) Å] and one long [2.516(3) Å] Zn–O bond, the metal–ligand interaction being intermediate between symmetrical chelation and syn-unidentate nitrito coordination. It seems likely that this unsymmetrical geometry is adopted in order to minimize ligand–ligand repulsions, though density functional theory calculations suggest a very shallow potential energy curve for the complex.

scholarly journals The crystal structure of Rb2Ti2O5

2017 ◽  
Vol 73 (6) ◽  
pp. 1142-1150 ◽  
Author(s):  
Rémi Federicci ◽  
Benoit Baptiste ◽  
Fabio Finocchi ◽  
Florin Popa ◽  
Luc Brohan ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Density Functional ◽  
Structural Transition ◽  
Ferroelectric Phase ◽  
Density Functional Theory Calculations ◽  
X Ray Diffraction ◽  
Functional Theory ◽  
X Ray ◽  
Transmission Electron ◽  
The Stability

Recent results have demonstrated an exceptionally high permittivity in the range 200–330 K in crystalline titanium oxide Rb2Ti2O5. In this article, the possibility of a structural transition giving rise to ferroelectricity is carefully inspected. In particular, X-ray diffraction, high-resolution transmission electron microscopy and Raman spectroscopy are performed. The crystal structure is shown to remain invariant and centrosymmetric at all temperatures between 90 K and 450 K. The stability of the C2/m structure is confirmed by density functional theory calculations. These important findings allow the existence of a conventional ferroelectric phase transition to be ruled out as a possible mechanism for the colossal permittivity and polarization observed in this material.

On tungstates of divalent cations (III) – Pb5O2[WO6]

2020 ◽  
Vol 235 (8-9) ◽  
pp. 311-317
Author(s):  
Stephan G. Jantz ◽  
Florian Pielnhofer ◽  
Henning A. Höppe
Keyword(s):  
Crystal Structure ◽  
Thermal Analysis ◽  
Quantum Chemical ◽  
Density Functional ◽  
Divalent Cations ◽  
X Ray Diffraction ◽  
Functional Theory ◽  
X Ray ◽  
First Results ◽  
Electrostatic Calculations

Abstract${\text{Pb}}_{5}{\text{O}}_{2}\left[{\text{WO}}_{6}\right]$ was discovered as a frequently observed side phase during our investigation on lead tungstates. Its crystal structure was solved by single-crystal X-ray diffraction ($P{2}_{1}/n$, $a=7.4379\left(2\right)$ Å, $b=12.1115\left(4\right)$ Å, $c=10.6171\left(3\right)$ Å, $\beta =90.6847\left(8\right)$°, $Z=4$, ${R}_{\text{int}}=0.038$, ${R}_{1}=0.020$, $\omega {R}_{2}=0.029$, 4188 data, 128 param.) and is isotypic with ${\text{Pb}}_{5}{\text{O}}_{2}\left[{\text{Te}}_{6}\right]$. ${\text{Pb}}_{5}{\text{O}}_{2}\left[{\text{WO}}_{6}\right]$ comprises a layered structure built up by non-condensed [WO6]${}^{6-}$ octahedra and ${\left[{\text{O}}_{4}{\text{Pb}}_{10}\right]}^{12+}$ oligomers. The compound was characterised by spectroscopic measurements (Infrared (IR), Raman and Ultraviolet–visible (UV/Vis) spectra) as well as quantum chemical and electrostatic calculations (density functional theory (DFT), MAPLE) yielding a band gap of 2.9 eV fitting well with the optical one of 2.8 eV. An estimation of the refractive index based on the Gladstone-Dale relationship yielded $n\approx 2.31$. Furthermore first results of the thermal analysis are presented.

A mononuclear cobalt(III) 3-(2-pyridyl)-5-phenyl-1,2,4-triazolato complex: hydrothermal synthesis, crystal structure, thermostability, and DFT calculations

2015 ◽  
Vol 70 (9) ◽  
pp. 631-636 ◽  
Author(s):  
Huaixian Liu ◽  
Lin Sun ◽  
Huiliang Zhou ◽  
Peipei Cen ◽  
Xiaoyong Jin ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Density Functional ◽  
Free Ligand ◽  
Supramolecular Network ◽  
Stacking Interactions ◽  
X Ray Diffraction ◽  
Hydrothermal Conditions ◽  
Functional Theory ◽  
X Ray ◽  
Mononuclear Cobalt

AbstractStarting with 1H-3-phenyl-5-(pyridin-2-yl)-1,2,4-triazole (1-Hppt), a Co(III) complex, [Co(ppt)3] (1), has been synthesized by reaction with CoF3 under hydrothermal conditions and characterized by its infrared spectrum and elemental analysis. The structure was determined by single-crystal and powder X-ray diffraction. Density functional theory (DFT) was employed to determine the optimized geometry and preferred conformation of the free ligand. A supramolecular network is formed via π–π stacking interactions. The conformation and geometry of the ligands correspond with the calculated results.

scholarly journals Synthesis, Characterization, and Crystal Structure Determination of a New Lithium Zinc Iodate Polymorph LiZn(IO3)3

Crystals ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 464 ◽  
Author(s):  
Hebboul ◽  
Galez ◽  
Benbertal ◽  
Beauquis ◽  
Mugnier ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Density Functional Theory ◽  
Density Functional ◽  
Second Harmonic ◽  
Infrared Absorption Spectrum ◽  
Density Functional Theory Calculations ◽  
Functional Theory ◽  
Space Group ◽  
X Ray ◽  
Cell Parameters

Synthesis and characterization of anhydrous LiZn(IO3)3 powders prepared from an aqueous solution are reported. Morphological and compositional analyses were carried out by using scanning electron microscopy and energy-dispersive X-ray measurements. The synthesized powders exhibited a needle-like morphology after annealing at 400 °C. A crystal structure for the synthesized compound was proposed from powder X-ray diffraction and density-functional theory calculations. Rietveld refinements led to a monoclinic structure, which can be described with space group P21, number 4, and unit-cell parameters a = 21.874(9) Å, b = 5.171(2) Å, c = 5.433(2) Å, and  = 120.93(4)°. Density-functional theory calculations supported the same crystal structure. Infrared spectra were also collected, and the vibrations associated with the different modes were discussed. The non-centrosymmetric space group determined for this new polymorph of LiZn(IO3)3, the characteristics of its infrared absorption spectrum, and the observed second-harmonic generation suggest it is a promising infrared non-linear optical material.

A high-pressure study of HfC and nano-crystalline TiC by X-ray diffraction and density functional theory calculations

2020 ◽  
Vol 34 (34) ◽  
pp. 2050393
Author(s):  
Lun Xiong ◽  
Bin Li ◽  
Bi Liang ◽  
Jinxia Zhu ◽  
Hong Yi ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
High Pressure ◽  
Bulk Modulus ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
Functional Theory ◽  
X Ray ◽  
Nano Crystalline

The equation of state (EOS) of HfC and nanosized TiC at high pressure has been studied by means of synchrotron radiation X-ray diffraction (XRD) in a diamond anvil cell (DAC) at ambient temperature, and density functional theory (DFT) calculations. XRD analysis showed that the cubic structure of HfC and nanosized TiC maintained to the maximum pressures. The XRD data yield a bulk modulus [Formula: see text] GPa with [Formula: see text] of HfC. In addition, the bulk modulus of nanosized TiC derived from XRD data is [Formula: see text] GPa with [Formula: see text].

Investigation of Structural Evolution of Li1.1V3O8 by In Situ X-ray Diffraction and Density Functional Theory Calculations

2017 ◽  
Vol 29 (5) ◽  
pp. 2364-2373 ◽  
Author(s):  
Qing Zhang ◽  
Alexander B. Brady ◽  
Christopher J. Pelliccione ◽  
David C. Bock ◽  
Andrea M. Bruck ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Structural Evolution ◽  
Density Functional Theory Calculations ◽  
X Ray Diffraction ◽  
Functional Theory ◽  
X Ray

scholarly journals Experimental and theoretical charge density distribution in Pigment Yellow 101

2015 ◽  
Vol 17 (6) ◽  
pp. 4677-4686 ◽  
Author(s):  
Jonathan J. Du ◽  
Linda Váradi ◽  
Jinlong Tan ◽  
Yiliang Zhao ◽  
Paul W. Groundwater ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Density Distribution ◽  
Charge Density ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
X Ray Diffraction ◽  
Charge Density Distribution ◽  
Functional Theory ◽  
X Ray ◽  
Multipole Refinement

The charge density distribution in 2,2′-dihydroxy-1,1′-naphthalazine (Pigment Yellow 101; P.Y.101) has been determined using high-resolution X-ray diffraction and multipole refinement, along with density functional theory calculations.

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