scholarly journals Functional Perovskites: Structure-Properties Correlations

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
A.K. Bera ◽  
S.M. Yusuf
Keyword(s):  
Physical Properties ◽  
Crystal Structures ◽  
General Formula ◽  
Perovskite Structure ◽  
Large Range ◽  
Catalytic Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Oxide Perovskite ◽  
Structure Properties

The perovskite structure with general formula ABX3 shows its multidimensional nature in regards to correlations of crystal structures with electronic, magnetic, optical, and catalytic properties. Perovskites are utilized in a large range of applications due to their tremendous versatility. In this chapter, structure-properties correlations in oxide perovskite compounds ABO3 having several functional properties are presented. In particular, neutron and x-ray diffraction results are described to reveal a direct correlation of several important physical properties, such as magnetic, multiferroic, electronic (CMR), and SOFC electrodes with the crystal structures.

Effect of La2O3 substitutions on structure and dielectric properties of Bi2O3–ZnO–Nb2O5-based pyrochlore ceramics

1999 ◽  
Vol 14 (2) ◽  
pp. 546-548 ◽  
Author(s):  
Hong Wang ◽  
Desheng Zhang ◽  
Xiaoli Wang ◽  
Xi Yao
Keyword(s):  
Crystal Structure ◽  
Dielectric Properties ◽  
Crystal Structures ◽  
Structure Change ◽  
Lower Amount ◽  
Ceramic Processing ◽  
X Ray Diffraction ◽  
X Ray ◽  
Conventional Ceramic Processing ◽  
Structure Properties

The effect of La2O3 substitutions on structure and dielectric properties of Bi2O3 –ZnO–Nb2O5-based ceramics was investigated. Bi1.5-xLaxZn0.5(Zn0.5Nb1.5)O7 samples were prepared by conventional ceramic processing technology. The crystal structure of the Bi1.5Zn0.5(Zn0.5Nb1.5)O7 sample was characterized as a pure cubic pyrochlore. With a lower amount of La2O3 substitution, the crystal structures were still cubic pyrochlore. Superlattice x-ray diffraction line was identified for some compositions. With the increasing amount of La2O3 substitution, the crystal structure gradually transformed from pure cubic pyrochlore to LaNbO4 phase. The dielectric properties regularly changed with the structure change. The structure-properties relations of the ceramics are discussed.

Calculation of Structural Parameters in Isostructural Series: the Kieserite Group

1998 ◽  
Vol 54 (5) ◽  
pp. 564-567 ◽  
Author(s):  
S. Aleksovska ◽  
V. M. Petrusevski ◽  
B. Soptrajanov
Keyword(s):  
Crystal Structures ◽  
General Formula ◽  
Structural Parameters ◽  
Unit Cell ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
Ionic Radii ◽  
X Ray ◽  
Cell Parameters ◽  
Atomic Coordinates

In order to demonstrate the possibility of predicting the structural parameters of members in a sequence of isostructural compounds, the kieserite group isotypes (with the general formula M II XO4.H2O) were chosen since a number of them have accurately refined crystal structures. The unit-cell parameters and the fractional atomic coordinates were shown to vary linearly with both cation and anion size. This makes it possible to calculate the structural parameters of a particular member, taking into account only the effective ionic radii of the constituent atoms. Agreement between the calculated and experimentally refined (by X-ray diffraction) structural parameters is good. The cell constants and atomic coordinates of FeSeO4.H2O, iron selenate monohydrate, are predicted in this way.

M+M3+2As(HAsO4)6and α- and β-M+M3+(HAsO4)2(M+M3+= RbAl or CsFe): six new compounds crystallizing in three closely related structure types

2018 ◽  
Vol 74 (6) ◽  
pp. 721-727 ◽  
Author(s):  
Karolina Schwendtner ◽  
Uwe Kolitsch
Keyword(s):  
Single Crystal ◽  
Crystal Structures ◽  
General Formula ◽  
Structure Type ◽  
Group Symmetry ◽  
Charge Balance ◽  
X Ray Diffraction ◽  
X Ray ◽  
Stacking Order ◽  
New Compounds

The crystal structures of hydrothermally synthesized (T= 493 K, 7–9 d) rubidium aluminium bis[hydrogen arsenate(V)], RbAl(HAsO4)2, caesium iron bis[hydrogen arsenate(V)], CsFe(HAsO4)2, rubidium dialuminium arsenic(V) hexakis[hydrogen arsenate(V)], RbAl2As(HAsO4)6, and caesium diiron arsenic(V) hexakis[hydrogen arsenate(V)], CsFe2As(HAsO4)6, were solved by single-crystal X-ray diffraction. The four compounds with the general formulaM+M3+(HAsO4)2adopt the RbFe(HPO4)2structure type (R\overline{3}c) and a closely related new structure type, which is characterized by a different stacking order of the building units, leading to noncentrosymmetric space-group symmetryR32. The second new structure type, with the general formulaM+M3+2As(HAsO4)6(R\overline{3}c), is also a modification of the RbFe(HPO4)2structure type, in which one third of theM3+O6octahedra are replaced by AsO6octahedra, and two thirds of the voids in the structure, which are usually filled byM+cations, remain empty to achieve charge balance.

A quinoxaline-fused tetrathiafulvalene derivative and its semiconducting charge-transfer salt: synthesis, crystal structures and physical properties

2014 ◽  
Vol 38 (5) ◽  
pp. 2052-2057 ◽  
Author(s):  
Yan Geng ◽  
Christoph Fiolka ◽  
Karl Krämer ◽  
Jürg Hauser ◽  
Vladimir Laukhin ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Charge Transfer ◽  
Physical Properties ◽  
Single Crystal ◽  
Crystal Structures ◽  
Single Crystal Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Donor Acceptor ◽  
Tetrathiafulvalene Derivative

A quinoxaline-fused tetrathiafulvalene (TTF) derivative 1 has been synthesized to form a compact and planar π-conjugated donor–acceptor (D–π–A) ensemble, and its single crystal structure has been determined by X-ray diffraction.

Syntheses, structures, and catalytic properties of two arene-ruthenium(II) complexes bearing N-(2-pyridinyl)aminodiphenylphosphine sulfide ligands

2018 ◽  
Vol 73 (3-4) ◽  
pp. 161-166
Author(s):  
Fule Wu ◽  
Jiling Gu ◽  
Xin Chen ◽  
Ai-Quan Jia ◽  
Qian-Feng Zhang
Keyword(s):  
Mass Spectrometry ◽  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Single Crystal ◽  
Crystal Structures ◽  
Catalytic Properties ◽  
Transfer Hydrogenation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sulfide Ligands

AbstractTreatment of [(arene)Ru(μ-Cl)Cl]2with Ph2P(S)NH(2-py) in the presence or absence of base gave two arene-ruthenium(II) complexes [(η6-p-cymene)Ru{κ2-N,N-Ph2P(S)N(2-py)}Cl] (1) and [(η6-benzene)Ru{κ1-N-Ph2P(S)NH(2-py)}Cl2] (2), which have been characterized by infrared, nuclear magnetic resonance spectroscopies, and mass spectrometry along with microanalyses. Crystal structures of Ph2P(S)NH(2-py) · ¼C6H14,1and2· ½CH2Cl2were determined by single-crystal X-ray diffraction. Two arene-ruthenium(II) complexes were tested as precatalysts for the transfer hydrogenation of acetophenone to give 1-phenyl ethanol.

Transmission electron microscope studies in special ceramics

1978 ◽  
Vol 36 (1) ◽  
pp. 268-269
Author(s):  
A. Zangvil ◽  
L.J. Gauckler ◽  
G. Schneider ◽  
M. Rühle
Keyword(s):  
Phase Diagrams ◽  
Crystal Structures ◽  
Thin Foil ◽  
Limited Extent ◽  
Complex Materials ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Electron Microscopes ◽  
Lattice Resolution

The use of high temperature special ceramics which are usually complex materials based on oxides, nitrides, carbides and borides of silicon and aluminum, is critically dependent on their thermomechanical and other physical properties. The investigations of the phase diagrams, crystal structures and microstructural features are essential for better understanding of the macro-properties. Phase diagrams and crystal structures have been studied mainly by X-ray diffraction (XRD). Transmission electron microscopy (TEM) has contributed to this field to a very limited extent; it has been used more extensively in the study of microstructure, phase transformations and lattice defects. Often only TEM can give solutions to numerous problems in the above fields, since the various phases exist in extremely fine grains and subgrain structures; single crystals of appreciable size are often not available. Examples with some of our experimental results from two multicomponent systems are presented here. The standard ion thinning technique was used for the preparation of thin foil samples, which were then investigated with JEOL 200A and Siemens ELMISKOP 102 (for the lattice resolution work) electron microscopes.

Microstructure and Physical Properties of Clay-Polymer Composites

2000 ◽  
Vol 628 ◽  
Author(s):  
T.N. Blanton ◽  
D. Majumdar ◽  
S.M. Melpolder
Keyword(s):  
Composite Materials ◽  
Physical Properties ◽  
Polymer Composites ◽  
Basal Plane ◽  
X Ray Diffraction ◽  
X Ray ◽  
Layered Clay

ABSTRACTClay-polymer nanoparticulate composite materials are evaluated by the X-ray diffraction technique. The basal plane spacing provided information about the degree of intercalation and exfoliation of the 2: 1 layered clay structure. Both intercalation and exfoliation are controlled by the identity of the polymer and the clay:polymer ratio.

Physicochemical and Catalytic Properties of Spinels Formed by Solid-Solid Interaction Between Fe2O3and V2O5

1996 ◽  
Vol 61 (8) ◽  
pp. 1131-1140 ◽  
Author(s):  
Abd El-Aziz Ahmed Said
Keyword(s):  
Vanadium Oxide ◽  
Active Sites ◽  
Catalyst Surface ◽  
Catalytic Properties ◽  
Flow System ◽  
Oxide Catalysts ◽  
X Ray Diffraction ◽  
Selective Catalyst ◽  
X Ray ◽  
Solid Catalysts

Vanadium oxide catalysts doped or mixed with 1-50 mole % Fe3+ ions were prepared. The structure of the original samples and those calcined from 200 up to 500 °C were characterized by TG, DTA, IR and X-ray diffraction. The SBET values and texture of the solid catalysts were investigated. The catalytic dehydration-dehydrogenation of isopropanol was carried out at 200 °C using a flow system. The results obtained showed an observable decrease in the activity of V2O5 on the addition of Fe3+ ions. Moreover, Fe2V4O13 is the more active and selective catalyst than FeVO4 spinels. The results were correlated with the active sites created on the catalyst surface.

scholarly journals An investigation of polyhedral deformation in two mixed-metal diarsenates: SrZnAs2O7and BaCuAs2O7

2015 ◽  
Vol 71 (4) ◽  
pp. 330-337 ◽  
Author(s):  
Sabina Kovač ◽  
Ljiljana Karanović ◽  
Tamara Đorđević
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
General Formula ◽  
Three Dimensional ◽  
X Ray Diffraction ◽  
Hydrothermal Conditions ◽  
X Ray ◽  
Open Framework ◽  
Geometrical Characteristics ◽  
Barium Copper

Two isostructural diarsenates, SrZnAs2O7(strontium zinc diarsenate), (I), and BaCuAs2O7[barium copper(II) diarsenate], (II), have been synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction. The three-dimensional open-framework crystal structure consists of corner-sharingM2O5(M2 = Zn or Cu) square pyramids and diarsenate (As2O7) groups. Each As2O7group shares its five corners with five differentM2O5square pyramids. The resulting framework delimits two types of tunnels aligned parallel to the [010] and [100] directions where the large divalent nine-coordinatedM1 (M1 = Sr or Ba) cations are located. The geometrical characteristics of theM1O9,M2O5and As2O7groups of known isostructural diarsenates, adopting the general formulaM1IIM2IIAs2O7(M1II= Sr, Ba, Pb;M2II= Mg, Co, Cu, Zn) and crystallizing in the space groupP21/n, are presented and discussed.

scholarly journals Crystal Chemical Relations in the Shchurovskyite Family: Synthesis and Crystal Structures of K2Cu[Cu3O]2(PO4)4 and K2.35Cu0.825[Cu3O]2(PO4)4

Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 807
Author(s):  
Ilya V. Kornyakov ◽  
Sergey V. Krivovichev
Keyword(s):  
Crystal Structure ◽  
Crystal Structures ◽  
Structural Complexity ◽  
Crystal Chemical ◽  
X Ray Diffraction ◽  
Complexity Measures ◽  
X Ray ◽  
The Family ◽  
Similarities And Differences ◽  
Related Compounds

Single crystals of two novel shchurovskyite-related compounds, K2Cu[Cu3O]2(PO4)4 (1) and K2.35Cu0.825[Cu3O]2(PO4)4 (2), were synthesized by crystallization from gaseous phase and structurally characterized using single-crystal X-ray diffraction analysis. The crystal structures of both compounds are based upon similar Cu-based layers, formed by rods of the [O2Cu6] dimers of oxocentered (OCu4) tetrahedra. The topologies of the layers show both similarities and differences from the shchurovskyite-type layers. The layers are connected in different fashions via additional Cu atoms located in the interlayer, in contrast to shchurovskyite, where the layers are linked by Ca2+ cations. The structures of the shchurovskyite family are characterized using information-based structural complexity measures, which demonstrate that the crystal structure of 1 is the simplest one, whereas that of 2 is the most complex in the family.

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