scholarly journals The strongly defective double perovskite Sr11Mo4O23: crystal structure in relation to ionic conductivity

2014 ◽  
Vol 47 (4) ◽  
pp. 1395-1401 ◽  
Author(s):  
Carlos A. López ◽  
José C. Pedregosa ◽  
Diego G. Lamas ◽  
José A. Alonso
Keyword(s):  
Crystal Structure ◽  
Ionic Conductivity ◽  
Powder Diffraction ◽  
Double Perovskite ◽  
Ionic Mobility ◽  
Neutron Powder Diffraction Data ◽  
Complex Crystal Structure ◽  
Citrate Precursors ◽  
The Relationship ◽  
Complex Crystal

The crystal structure and ionic conductivity properties of a novel microcrystalline Sr11Mo4O23ceramic material are presented. This material has been prepared by thermal treatment up to 1473 K, in air, of previously decomposed citrate precursors. The complex crystal structure was refined from combined X-ray powder diffraction and neutron powder diffraction data. The formula of this phase can be rewritten as Sr1.75□0.25SrMoO5.75, highlighting the relationship with double perovskitesA2B′B′′O6. At room temperature, the crystal structure is tetragonal in space groupI41/a, witha= 11.6107 (6) Å,c= 16.422 (1) Å andV = 2213.8 (2) Å3. The crystal network contains O anion and Sr cation vacancies. The structure is complex, with Sr, Mo and O atoms distributed over four, two and six distinct Wyckoff sites, respectively. Only one of the Sr sites (SrO6) corresponds to the octahedral network; one of the two MoO6types of octahedra is axially distorted. The three other Sr positions occupy theAsite with higher coordination. There is an occupational deficit of O atoms of 22 (4)%. This defective framework material presents an interesting ionic mobility, enhanced above 773 K owing to a further reduction in the oxygen content.

scholarly journals Crystal structure, hydrogen bonding, mechanical properties and Raman spectrum of the lead uranyl silicate monohydrate mineral kasolite

RSC Advances ◽  
2019 ◽  
Vol 9 (27) ◽  
pp. 15323-15334 ◽  
Author(s):  
Francisco Colmenero ◽  
Jakub Plášil ◽  
Joaquín Cobos ◽  
Jiří Sejkora ◽  
Vicente Timón ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Mechanical Properties ◽  
Hydrogen Bonding ◽  
Raman Spectrum ◽  
Mechanical Behavior ◽  
New Method ◽  
Complex Crystal Structure ◽  
Detailed Interpretation ◽  
The Relationship ◽  
Complex Crystal

A profound understanding of the relationship between the complex crystal structure of kasolite and its mechanical behavior is provided. A detailed interpretation of its Raman spectrum and a new method for band resolution are reported.

Relationship Between Crystal Structure and Li+-Conductivity in La0.5 Li0.5TiO3 Perovskite

1999 ◽  
Vol 575 ◽  
Author(s):  
J. A. Alonso ◽  
J. Ibarra ◽  
M. A. Paris ◽  
J. Sanz ◽  
J. Santamaria ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Ionic Conductivity ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Perovskite Structure ◽  
Neutron Powder Diffraction ◽  
Powder Diffraction Data ◽  
Conducting Material ◽  
Neutron Powder Diffraction Data ◽  
First Time

ABSTRACTFor the first time Li+ cations have been localized within the perovskite structure of the fast Liconductor La0 5Li0.5TiO3 from neutron powder diffraction data. Li cations are fourfold oxygen coordinated, located in the middle of the almost square windows determined by every four TiO6 octahedra, far away from the 12-fold coordinated La vacancy sites that, nevertheless, take part of the path for Li motion across the solid. The large multiplicity of the sites where Li reside (1/6 occupied) accounts for the huge ionic conductivity of this promising Li-conducting material.

Use of Neutron Diffraction for Describing Texture of Isostatically-Pressed Molybdite Powders

2005 ◽  
Vol 105 ◽  
pp. 83-88 ◽  
Author(s):  
H. Sitepu ◽  
Heinz Günter Brokmeier
Keyword(s):  
Crystal Structure ◽  
Neutron Diffraction ◽  
Powder Diffraction ◽  
Quantitative Description ◽  
Neutron Powder Diffraction ◽  
Powder Diffraction Data ◽  
Neutron Powder Diffraction Data ◽  
Pole Figures ◽  
Diffraction Patterns ◽  
Excellent Tool

The modelling and/or describing of texture (i.e. preferred crystallographic orientation (PO)) is of critical importance in powder diffraction analysis - for structural study and phase composition. In the present study, the GSAS Rietveld refinement with generalized spherical harmonic (GSH) was used for describing isostatically-pressed molybdite powders neutron powder diffraction data collected in the ILL D1A instrument. The results showed that for texture in a single ND data of molybdite the reasonable crystal structure parameters may be obtained when applying corrections to intensities using the GSH description. Furthermore, the WIMV method was used to extract the texture description directly from a simultaneous refinement with 1368 whole neutron diffraction patterns taken from the sample held in a variety of orientations in the ILL D1B texture goniometer. The results provided a quantitative description of the texture refined simultaneously with the crystal structure. Finally, the (002) molybdite pole-figures were measured using the GKSS TEX2 texture goniometer. The results showed that neutron diffraction is an excellent tool to investigate the texture in molybdite.

A Novel Example of Metal-Mediated Aromatic Thiolation in a Ruthenium Complex. Crystal Structure of RuII(SC6H4NNC6H4N)2†

1996 ◽  
Vol 35 (10) ◽  
pp. 3050-3052 ◽  
Author(s):  
Bidyut Kumar Santra ◽  
Ganesh A. Thakur ◽  
Prasanta Ghosh ◽  
Amitava Pramanik ◽  
Goutam Kumar Lahiri
Keyword(s):  
Crystal Structure ◽  
Ruthenium Complex ◽  
Complex Crystal Structure ◽  
Complex Crystal
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