Formation of BaPbO3-x and BaPb1/3Bi2/3O3-x from Ba(COO)2⋅0.5H2O and Pb(COO)2 oxalates

MRS Advances ◽  
2020 ◽  
Vol 5 (51) ◽  
pp. 2647-2658
Author(s):  
Barys Korzun ◽  
Alena Fadzeyeva ◽  
Joel Hernandez
Keyword(s):  
Crystal Structure ◽  
Thermal Analysis ◽  
Thermal Decomposition ◽  
Single Phase ◽  
Monoclinic Crystal ◽  
X Ray ◽  
Monoclinic Crystal Structure ◽  
Subsequent Calcination ◽  
Initial Preparation ◽  
Perovskite Type

AbstractThis paper reports a way to obtain BaPbO3-x and BaPb1/3Bi2/3O3-x perovskite-type compounds. The method is based on the initial preparation of Ba(COO)2⋅0.5H2O and Pb(COO)2⋅oxalates, and the subsequent calcination of the equimolar physical mixture of these oxalates until the desired compounds BaPbO3-x and BaPb1/3Bi2/3O3-x are formed. To obtain BaPb1/3Bi2/3O3-x, the oxide Bi2O3 is added to the mixture of oxalates and calcined together with them. The temperature for the formation of BaPbO3-x and BaPb1/3Bi2/3O3-x was estimated to be 850°C. These final compounds prepared by calcination were composed of a single phase and exhibited monoclinic crystal structure. The thermal decomposition of the Pb(COO)2 oxalate and the formation of BaPbO3-x and BaPb1/3Bi2/3O3-x were investigated by X-ray powder diffraction (XRPD) and differential thermal analysis (DTA).

Preparation, Crystal Structure, and Properties of the Lanthanoid Carbides Ln4C7 with Ln = Ho, Er, Tm, and Lu

1996 ◽  
Vol 51 (5) ◽  
pp. 646-654 ◽  
Author(s):  
Ralf Czekalla ◽  
Wolfgang Jeitschko ◽  
Rolf-Dieter Hoffmann ◽  
Helmut Rabeneck
Keyword(s):  
Crystal Structure ◽  
Rietveld Method ◽  
Magnetic Ordering ◽  
Monoclinic Crystal ◽  
X Ray ◽  
Neutron Powder Diffraction Data ◽  
Monoclinic Crystal Structure ◽  
Arc Melting ◽  
Structure Factors ◽  
Hydrolysis Of

The isotypic carbides Ln4C7 (Ln = Ho, Er, Tm, Lu) were prepared by arc-melting of the elemental components, followed by annealing at 1300 °C. The positions of the metal and of some carbon atoms of the monoclinic crystal structure of LU4C7 were determined from X-ray powder data, and the last carbon positions were found and refined from neutron powder diffraction data: P21/c, a = 360.4(1), b = 1351.4(3), c = 629.0(2) pm, β = 104.97(2)°, Z = 2, R = 0.026 for 429 structure factors and 15 positional parameters. The structure contains isolated carbon atoms with octahedral lutetium coordination and linear C3-units, with C-C bond lengths of 132(1) and 135(1) pm. This carbide may therefore be considered as derived from methane and propadiene. The hydrolysis of LU4C7 with distilled water yields mainly methane and propine, while the hydrolyses of the corresponding holmium and erbium carbides resulted in relatively large amounts of saturated and unsaturated C2-hydrocarbons in addition to the expected products methane and propine. The structure comprises two-dimensionally infinite NaCl-type building elements, which are separated by the C3-units. It may be described as a stacking variant of a previously reported structure of HO4C7, now designated as the a-modification. The Lu4C7-type β -modification was obtained at higher temperatures. Its structure was refined by the Rietveld method from X-ray powder data to a residual R = 0.037 for 320 F values and 15 positional parameters. Lu4C7 is Pauli paramagnetic; β -HO4C7 and Er4C7 show Curie-Weiss behavior with magnetic ordering temperatures of less than 20 K.

Electron density, disorder and polymorphism: high-resolution diffraction studies of the highly polymorphic neuralgic drug carbamazepine

2016 ◽  
Vol 72 (1) ◽  
pp. 39-50 ◽  
Author(s):  
Ioana Sovago ◽  
Matthias J. Gutmann ◽  
Hans Martin Senn ◽  
Lynne H. Thomas ◽  
Chick C. Wilson ◽  
...  
Keyword(s):  
Crystal Structure ◽  
High Resolution ◽  
Diffraction Data ◽  
Structural Formula ◽  
Orthorhombic Crystal ◽  
Monoclinic Crystal ◽  
Orthorhombic Crystal Structure ◽  
Space Group ◽  
X Ray ◽  
Monoclinic Crystal Structure

Analysis of neutron and high-resolution X-ray diffraction data on form (III) of carbamazepine at 100 K using the atoms in molecules (AIM) topological approach afforded excellent agreement between the experimental results and theoretical densities from the optimized gas-phase structure and from multipole modelling of static theoretical structure factors. The charge density analysis provides experimental confirmation of the partially localized π-bonding suggested by the conventional structural formula, but the evidence for any significant C—N π bonding is not strong. Hirshfeld atom refinement (HAR) gives H atom positional and anisotropic displacement parameters that agree very well with the neutron parameters. X-ray and neutron diffraction data on the dihydrate of carbemazepine strongly indicate a disordered orthorhombic crystal structure in the space groupCmca, rather than a monoclinic crystal structure in space groupP21/c. This disorder in the dihydrate structure has implications for both experimental and theoretical studies of polymorphism.

Crystal Structure of BiFeO3 Synthesized Using the Hydrothermal Processing

2014 ◽  
Vol 602-603 ◽  
pp. 947-950
Author(s):  
Zhen Wang ◽  
Hai Yan Chen ◽  
Lin Qiang Gao ◽  
Xin Zou
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Thermal Analysis ◽  
Scanning Electron Microscopy ◽  
Single Phase ◽  
Hydrothermal Processing ◽  
Optimal Conditions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

BiFeO3 nanoparticles were successfully synthesized by a hydrothermal method by a mineralizer (KNO3). Structural characterization was performed by thermal analysis, powder X-ray diffraction (XRD) and scanning electron microscopy (TEM).The results showed that the products were perovskite structure BiFeO3 powders. Optimal conditions for the synthesis of single-phase BiFeO3 ceramics were obtained.

scholarly journals A new crystalline form of αβ-D-lactose prepared by oven drying a concentrated aqueous solution of D-lactose

2019 ◽  
Vol 75 (7) ◽  
pp. 904-909 ◽  
Author(s):  
Daniel Nicholls ◽  
Carole Elleman ◽  
Norman Shankland ◽  
Kenneth Shankland
Keyword(s):  
Crystal Structure ◽  
Aqueous Solution ◽  
Three Dimensional ◽  
Crystalline Form ◽  
X Ray Diffraction ◽  
Monoclinic Crystal ◽  
X Ray ◽  
Monoclinic Crystal Structure ◽  
High Degree ◽  
Triclinic Form

A new crystalline form of αβ-D-lactose (C12H22O11) has been prepared by the rapid drying of an approximately 40% w/v syrup of D-lactose. Initially identified from its novel powder X-ray diffraction pattern, the monoclinic crystal structure was solved from a microcrystal recovered from the generally polycrystalline mixed-phase residue obtained at the end of the drying step. This is the second crystalline form of αβ-D-lactose to be identified and it has a high degree of structural three-dimensional similarity to the previously identified triclinic form.

Magnetic Structure and Properties of the Intercalated Compound Fe0.5TiSe2

2010 ◽  
Vol 168-169 ◽  
pp. 157-160 ◽  
Author(s):  
N.V. Baranov ◽  
N.V. Selezneva ◽  
Valery G. Pleshchev ◽  
N.V. Mushnikov ◽  
V.I. Maksimov
Keyword(s):  
Magnetic Field ◽  
Crystal Structure ◽  
Electrical Resistivity ◽  
Neutron Diffraction ◽  
Magnetic Moments ◽  
Structure And Properties ◽  
Monoclinic Crystal ◽  
X Ray ◽  
Monoclinic Crystal Structure ◽  
A Value

The intercalated compound Fe0.5TiSe2 has been studied by means of X-ray, neutron diffraction, electrical resistivity and magnetization measurements. This compound with Fe atoms located between Se-Ti-Se sandwiches has a monoclinic crystal structure and exhibits a long-range antiferromagnetic (AF) ordering below TN = 135 K. At T < TN, the Fe magnetic moments with a value ~ 3.0 µB are directed at an angle of (74.4±0.5)º to the layers and form a tilted antiferromagnetic structure with the propagation vector (½, 0, ½). It has been shown that application of magnetic field above 300 kOe may lead to transformations of the AF structure.

Thermal evolution of the microstructure of nanosized LaFeO3 powders from the thermal decomposition of a heteronuclear complex, La[Fe(CN)6] · 5H2O

1998 ◽  
Vol 13 (5) ◽  
pp. 1335-1344 ◽  
Author(s):  
Enrico Traversa ◽  
Patrizia Nunziante ◽  
Masatomi Sakamoto ◽  
Yoshihiko Sadaoka ◽  
Maria Cristina Carotta ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thermal Decomposition ◽  
Single Phase ◽  
Thermal Evolution ◽  
Nanosized Particles ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Perovskite Type ◽  
Heteronuclear Complex

The thermal decomposition of a heteronuclear complex, La[Fe(CN)6] · 5H2O, leads to the preparation of nanosized single-phase perovskite-type LaFeO3 powders. The microstructural evolution of LaFeO3 with the temperature has been studied by x-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The product of the decomposition at 500 °C consists of nanoporous grains which have the morphology of the complex, but diffracting as a monocrystal of LaFeO3. At the higher temperatures, the nanosized particles start to separate from each other, still keeping the shape of the complex grains and forming soft agglomerates. The formation of LaFeO3 from the complex at low temperatures is facilitated by the formation of an orthorhombic transition phase.

The crystal structure of (Ho0.50Ca0.50)MnO3 and its evolution with Cr doping: A Rietveld refinement investigation

2005 ◽  
Vol 20 (1) ◽  
pp. 22-26 ◽  
Author(s):  
A. Martinelli ◽  
M. Ferretti
Keyword(s):  
Crystal Structure ◽  
Single Phase ◽  
Rietveld Method ◽  
Ionic Species ◽  
X Ray ◽  
Jahn Teller ◽  
Bond Valence Sum ◽  
Perovskite Type ◽  
Cr Doping ◽  
Perovskite Type Structure

Single-phase (Ho0.50Ca0.50)MnO3 has been successfully prepared by means of solid state reaction at high temperature. Its crystal structure, as well as those of Cr-doped samples(Ho1−xCax)(Mn1−yCry)O3, has been refined by the Rietveld method, using X-ray powder diffraction data. All the examined compounds crystallize in the Pnma space group with a distorted perovskite-type structure. The distortion of the BO6 octahedra, due to the Jahn–Teller Mn3+ ionic species, decreases with the Cr content. Bond valence sum calculations were carried out using the refined results.

Identification of Crystal Structure and Crystallographic Features of NiMnGa Thin Films by Combination of X-Ray Diffraction (XRD) and Electron Backscatter Diffraction (EBSD)

2014 ◽  
Vol 783-786 ◽  
pp. 2561-2566
Author(s):  
Bo Yang ◽  
Zong Bin Li ◽  
Yu Dong Zhang ◽  
Claude Esling ◽  
Gao Wu Qin ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Electron Backscatter Diffraction ◽  
Substrate Surface ◽  
Monoclinic Crystal ◽  
X Ray ◽  
Lattice Constants ◽  
Monoclinic Crystal Structure ◽  
Pole Figures ◽  
Xrd Patterns ◽  
Backscatter Diffraction

In this work, NiMnGa thin film composed of non-modulated martensite (NM) and seven-layered modulated martensite (7M) was produced. The crystal structure and lattice constants were determined by X-ray diffractometer (XRD). The preferred crystallographic orientation of martensite was determined using the four-circle XRD. SEM/EBSD was employed to verify the crystal structure of the martensite and to reveal its crystallographic features correlated with the microstructure. According to the XRD patterns, the crystal structure of NM and 7M was determined as tetragonal and monoclinic crystal structure, respectively. Pole figures measured by four-circle diffractometer revealed that the NM martensite possesses (004)NM and (220)NM preferred plane texture close to the substrate surface, whereas the 7M martensite has (2 0 20)7M, (2 0 )7M and (040)7M preferred plane texture close to the substrate surface. SEM/EBSD analysis shows that the surface layer of the film is mainly composed of NM martensite that is organized in variant groups. In each variant group, all the martensite plates consist of paired lamellar (112)NM compound twins and there are eight orientation variants in each variant group.

Research on the Structure of GdFeMn Compound

2017 ◽  
Vol 1142 ◽  
pp. 14-18 ◽  
Author(s):  
Shi Qian Zhao ◽  
Lei Ma ◽  
Liang Zhou ◽  
Tao Liu ◽  
Yong Bin Guo
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Thermal Analysis ◽  
Solid Solution ◽  
Scanning Electron Microscopy ◽  
Differential Thermal Analysis ◽  
Rietveld Refinement ◽  
Single Phase ◽  
X Ray ◽  
Scanning Electron

The crystal structure of GdFeMn alloy has been investigated by using X-ray powder diffraction (XRD) followed by Rietveld refinement technique, differential thermal analysis (DTA) and scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDS) techniques. XRD results showed that annealed GdFeMn alloy was a single phase of Gd6(Fe0.5Mn0.5)23 compound, with Th6Mn23-structure. SEM/EDS results and Rietveld refinement revealed that GdFeMn alloy was not really a new ternary compound as reported, but a solid solution Gd6(Fe0.5Mn0.5)23 which was only a point between Gd6Fe23 and Gd6Mn23. It was also found from DTA measurement that a reaction, Gd (Fe0.5Mn0.5)2 → liquid (rich Gd) + Gd6(Fe0.5Mn0.5)23, had taken place above 650.81 oC, and the educed Gd existed in educed part of GdFeMn sample. The results demonstrated the real structure of the GdFeMn compound as reported was Gd6(Fe0.5Mn0.5)23 compound.

Sign in / Sign up

Export Citation Format

Share Document