X-ray diffraction data for the new ferroelectric tetragonal tungsten bronze phases, Ba2RETi2M3O15:M=Nb and RE=La, Pr, Nd, Sm, Gd, Dy, (Bi);M=Ta and RE=La, Nd

2005 ◽  
Vol 20 (1) ◽  
pp. 43-46 ◽  
Author(s):  
Gabrielle C. Miles ◽  
Martin C. Stennett ◽  
David Pickthall ◽  
Caroline A. Kirk ◽  
Ian M. Reaney ◽  
...  
Keyword(s):  
Diffraction Data ◽  
Tungsten Bronze ◽  
Lattice Parameter ◽  
X Ray Diffraction ◽  
Tungsten Bronze Structure ◽  
Tetragonal Tungsten Bronze ◽  
X Ray ◽  
Anomalous Data ◽  
Tetragonal Unit Cell ◽  
Ion Radius

X-ray powder diffraction data are presented for nine new phases with the tetragonal tungsten bronze structure. By comparison with the structure of the M=Nb,RE=La analogue, these contain Ba in the large pentagonal sites with coordination number 15, a range of large rare-earth cations and Bi in the twelve coordinate sites, and the smaller cations, Ti and either Nb or Ta, in the octahedral framework sites. The a lattice parameter data of the tetragonal unit cell show an approximately linear variation with trivalent ion radius, apart from Dy, whose value appears to be anomalous; data for c show little variation with trivalent ion radius.

Influence of Ti additions on the Texture and Dielectric Properties of LSBN-BST Complex Ceramics

1998 ◽  
Vol 541 ◽  
Author(s):  
J. Portelles ◽  
H. Amorín ◽  
J. M. Siqueiros ◽  
F.F. Castilión ◽  
E. Martínez ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Oxygen Vacancies ◽  
Tungsten Bronze ◽  
Material Structure ◽  
X Ray Diffraction ◽  
Strontium Barium ◽  
Tetragonal Tungsten Bronze ◽  
X Ray ◽  
First Results

AbstractThe stoichiometric La-Ti doped strontium-barium niobate ceramic system was obtained for different concentrations of Titanium ions (Ti=1,3,5,10,30,50 %), where the Nb5− was substituted by Ti4+ according to the following expression Sr0.255 La0.03Bao0.7Nb2−yTiyO6−y/2 (LSBN-BST). The oxygen vacancies thus created which, together with the vacancies in the A sites of the tetragonal tungsten-bronze (TTB) material structure, have an important influence on their texture and dielectric properties, due to the crucial role of the occupancy of the crystallographic sites. X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy and thermoelectric analyses are reported. We report the first results for thin films of LSBNT- 7 % obtained by the PLD technique. The diffraction pattern reveals the presence of the LSBNT structure without annealing.

scholarly journals Characterization of K6Ta10.8O30 Microrods with Tetragonal Tungsten Bronze-Like Structure Obtained from Tailings from the Penouta Sn-Ta-Nb Deposit

Nanomaterials ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 2289
Author(s):  
Belén Sotillo ◽  
Lorena Alcaraz ◽  
Félix A. López ◽  
Paloma Fernández
Keyword(s):  
Crystal Structure ◽  
Tungsten Bronze ◽  
X Ray Diffraction ◽  
Tetragonal Tungsten Bronze ◽  
X Ray ◽  
The North ◽  
Recovered Material ◽  
North Of Spain ◽  
Scanning Electron

In this work, a deep characterization of the properties of K6Ta10.8O30 microrods has been performed. The starting material used to grow the microrods has been recovered from mining tailings coming from the Penouta Sn-Ta-Nb deposit, located in the north of Spain. The recovered material has been submitted to a thermal treatment to grow the microrods. Then, they have been characterized by scanning electron microscopy, X-ray diffraction, micro-Raman and micro-photoluminescence. The results of our study confirm that the K6Ta10.8O30 microrods have a tetragonal tungsten bronze-like crystal structure, which can be useful for ion-batteries and photocatalysis.

Jarosite–butlerite intergrowths in non-stoichiometric jarosites: crystal chemistry of monoclinic natrojarosite–hydroniumjarosite phases

2011 ◽  
Vol 75 (6) ◽  
pp. 2775-2791 ◽  
Author(s):  
I. E. Grey ◽  
N. V. Y. Scarlett ◽  
P. Bordet ◽  
H. E. A. Brand
Keyword(s):  
Diffraction Data ◽  
Thermal Analyses ◽  
Reaction Times ◽  
Lattice Parameter ◽  
Recent Model ◽  
X Ray Diffraction ◽  
Iron Site ◽  
X Ray ◽  
Monoclinic Distortion ◽  
Deuterated Sample

AbstractMonoclinic, non-stoichiometric natrojarosite—hydroniumjarosite solid solution phases have been synthesized hydrothermally over a range of temperatures, starting compositions and reaction times, and have been characterized using Rietveld refinement of synchrotron X-ray diffraction data, and chemical and thermal analyses. The H atom locations have been obtained from refinement of neutron diffraction data on a deuterated sample. The results confirm a direct relationship between the monoclinic distortion and the ordering of iron site vacancies in one of two independent iron sites. Ordering of iron vacancies gives rise to domains containing butlerite-like 7 Å chains of corner-connected octahedra and tetrahedra. The formation of these chains within (100) planes results in an expansion of the monoclinic a lattice parameter and a contraction of the c parameter relative to stoichiometric jarosites. The results support a recent model for iron deficiency, whereby an iron vacancy is compensated by the replacement of four coordinated OH– ions by H2O molecules, with one of the H2O molecules coming from deprotonation of H3O+. The general formula, based on intergrowth of stoichiometric jarosite and non-stoichiometric, butlerite-like regions, is [(Na,H3O)Fe3(SO4)2(OH)6]1–y[(H2O)Fe2(SO4)2(OH)2(H2O)4]y.

Synthesis and X-ray powder diffraction data of Ba2.64Ta11.25O30.81

2014 ◽  
Vol 29 (4) ◽  
pp. 385-388 ◽  
Author(s):  
A. A. Babaryk ◽  
I. V. Odynets ◽  
S. Khainakov ◽  
N. S. Slobodyanik
Keyword(s):  
Single Phase ◽  
Tungsten Bronze ◽  
Rietveld Analysis ◽  
Structure Type ◽  
Tungsten Bronze Structure ◽  
Solid State Reaction Technique ◽  
Conventional Solid State Reaction ◽  
Tetragonal Tungsten Bronze ◽  
X Ray ◽  
Cell Parameters

The Ba2.64Ta11.25O30.81was prepared by conventional solid-state reaction technique as a single phase. It was found that the compound crystallizes in the tetragonal system, space group P4/mbm (No. 127) and unit-cell parameters are a = 12.508 59(8) Å, c = 3.912 81(2) Å, V = 612.218(7) Å3, and Z = 1. The crystal structure of the Ba2.64Ta11.25O30.81 phase is found to be closely related to the tetragonal tungsten bronze structure type, comprising interstitial (TaO)+ inclusions. Reference data were derived from the Rietveld analysis and reported here.

X-ray powder diffraction data for 1-adamantanol

1996 ◽  
Vol 11 (1) ◽  
pp. 24-25
Author(s):  
N. Bettahar ◽  
S. R. Salman
Keyword(s):  
Powder Diffraction ◽  
Diffraction Data ◽  
Unit Cell ◽  
Powder Diffraction Data ◽  
X Ray Diffraction ◽  
X Ray ◽  
Tetragonal Unit Cell

Indexed X-ray diffraction data are reported for 1-adamantanol. The data were indexed on a tetragonal unit cell with a=15.869 Å and c=6.879 Å, P44/nZ=8.

Rietveld refinement of ternary compound Gd117Fe52Ge112

2007 ◽  
Vol 22 (4) ◽  
pp. 312-315 ◽  
Author(s):  
Wei He ◽  
Jiliang Zhang ◽  
Lingmin Zeng
Keyword(s):  
Rietveld Refinement ◽  
Ternary Compound ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Figure Of Merit ◽  
Rietveld Method ◽  
Lattice Parameter ◽  
Powder Diffraction Data ◽  
X Ray Diffraction ◽  
X Ray

A new ternary compound Gd117Fe52Ge112 has been successfully synthesized and studied by means of X-ray powder diffraction technique. Gd117Fe52Ge112 crystallizes in a cubic Tb117Fe52Ge112-type structure with space group Fm3m(#225) and lattice parameter a=28.7680(1) Å. Crystal structure of Gd117Fe52Ge112 has been successfully refined using the Rietveld method from X-ray diffraction data. The R-factors for the Rietveld refinement are Rp=0.099 and Rwp=0.128. X-ray powder diffraction data with the figure of merit F30 of 80.4(30) are also reported.

1 MV super-high-resolution electron microscopy of Nb2O5-WO3complex compounds with TTB type subcells

1978 ◽  
Vol 36 (1) ◽  
pp. 298-299
Author(s):  
Shigeo Horiuchi
Keyword(s):  
Crystal Structure ◽  
High Resolution ◽  
Composition Range ◽  
Tungsten Bronze ◽  
High Resolution Electron Microscopy ◽  
X Ray Diffraction ◽  
Tetragonal Tungsten Bronze ◽  
X Ray ◽  
Voltage Electron ◽  
Resolution Electron

It is known that, over a composition range in a Nb2-O5-WO3 system, the crystal structure of compounds is composed of subcells with tetragonal tungsten bronze ( TIB ) type.) Different models have however been reported for some of them. The crystals are usually prepared in sealed tubes and sometimes show different colours due to a reduction in spite of a definite starting composition. Moreover, they frequently include small domains, which make the structure analysis by x-ray diffraction very difficult. In the present study we examine a series of these compounds, prepared under various conditions, by a super-high-resolution, high-voltage electron microscope ( Hitachi 1250 ),in which the lattice fringes of 2.0 Å in width can be resolved at an accelerating voltage of 1 MV under an axial illumination with equipping a specimen goniometer.2)Fig.l is a crystal structure image of 4Nb2O5.9WO3. According to electron diffractions the lattice parameters are a=12.3, b=36.6 and c=3.94 Å (orthorhombic).

Structural investigation of tungsten bronze-type relaxor ferroelectrics in the BaxSr3−xTiNb4O15 system

2014 ◽  
Vol 29 (S1) ◽  
pp. S15-S18
Author(s):  
Thomas A. Whittle ◽  
Siegbert Schmid
Keyword(s):  
Phase Transition ◽  
Diffraction Data ◽  
Structural Investigation ◽  
Tungsten Bronze ◽  
Relaxor Ferroelectrics ◽  
Cation Ordering ◽  
X Ray Diffraction ◽  
Rietveld Refinements ◽  
X Ray

Compounds in the BaxSr3−xTiNb4O15 series with x = 0.0–3.0 were synthesised. Synchrotron X-ray diffraction data were collected for each member synthesised. Rietveld refinements were performed for all compositions. A composition-dependent phase transition between orthorhombic and tetragonal symmetries was found. Cation ordering was observed between barium and strontium atoms in the two distinct A site cavities

High-Order Incommensurate Modulations and Incommensurate Superstructures in Transparent Sr0.6Ba0.4Nb2O6(SBN40) Ceramics

1998 ◽  
Vol 31 (5) ◽  
pp. 683-691 ◽  
Author(s):  
Han-Young Lee ◽  
R. Freer
Keyword(s):  
Tungsten Bronze ◽  
Higher Order ◽  
Processing Route ◽  
Microstructural Development ◽  
X Ray Diffraction ◽  
Tetragonal Tungsten Bronze ◽  
Planar Defects ◽  
X Ray ◽  
Transmission Electron ◽  
Structural Modulation

Ceramics of strontium barium niobate (Sr0.6Ba0.4Nb2O6, SBN40), having the tetragonal tungsten bronze (TTB) structure, were prepared by a conventional processing route; sintering at temperatures in the range 1573–1723 K yielded products with three types of microstructure. Incommensurate superstructures were investigated by transmission electron microscopy (TEM). Modulation of the incommensurate superstructure (ICS) depended on microstructural development. The lowest-order ICS modulation was a common feature in all the SBN40 ceramics, regardless of microstructure. (h+1/2,h+1/2,l) reflections and unusually low δ (incommensurability parameter) were observed in SBN40 specimens having abnormally large grains and thus a certain degree ofA-site ordering was expected. Transparent SBN40 ceramics which exhibited large homogeneous grains were characterized by a shortenedcaxis, intense [001] X-ray diffraction reflections, a multiplication of (110) and (001) cell spacings and the appearance of higher-order ICS reflections. Planar defects, having the thickness of one d_{110} spacing, were observed aligned along \{110\}. The development of a higher-order structural modulation and of ICS reflections is believed to reduce the structural energy; the development of planar defects appears to stabilize the incommensurate phase.

scholarly journals High-pressure synthesis and crystal structure of the mixed-cation borate Ga4In4B15O33(OH)3

2019 ◽  
Vol 74 (4) ◽  
pp. 357-363
Author(s):  
Daniela Vitzthum ◽  
Hubert Huppertz
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
High Temperature ◽  
Diffraction Data ◽  
X Ray Diffraction ◽  
Synthesis And Crystal Structure ◽  
X Ray ◽  
Mixed Cation ◽  
High Pressure High Temperature ◽  
Pressure Synthesis

AbstractThe mixed cation triel borate Ga4In4B15O33(OH)3 was synthesized in a Walker-type multianvil apparatus at high-pressure/high-temperature conditions of 12.5 GPa and 1300°C. Although the product could not be reproduced in further experiments, its crystal structure could be reliably determined via single-crystal X-ray diffraction data. Ga4In4B15O33(OH)3 crystallizes in the tetragonal space group I41/a (origin choice 2) with the lattice parameters a = 11.382(2), c = 15.244(2) Å, and V = 1974.9(4) Å3. The structure of the quaternary triel borate consists of a complex network of BO4 tetrahedra, edge-sharing InO6 octahedra in dinuclear units, and very dense edge-sharing GaO6 octahedra in tetranuclear units.

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