scholarly journals Characterization of Radium Sulphate

2013 ◽  
Vol 2013 ◽  
pp. 1-4 ◽  
Author(s):  
Hanna Hedström ◽  
Ingmar Persson ◽  
Gunnar Skarnemark ◽  
Christian Ekberg
Keyword(s):  
Substitutional Solid Solution ◽  
Barium Sulphate ◽  
X Ray Diffraction ◽  
Lead Sulphate ◽  
X Ray ◽  
Cell Parameters ◽  
Barium Strontium ◽  
The Mean ◽  
Sulphate Media

This paper examines the crystal structure of radium sulphate and compares its structure to barium sulphate, strontium sulphate, and lead sulphate. The radium sulphate powder was measured by both powder X-ray diffraction and EXAFS. The unit cell was determined to be orthorhombic, belonging to the Pnma (no. 62) space group with the cell parameters a=9.07 Å, b=5.52 Å, c=7.28 Å, and V=364.48 Å3. These data support the fact that radium sulphate is isostructural with barium, strontium, and lead sulphate. The bond distances were determined using EXAFS. The mean Ra–O and S–O bond distances were found to be 2.96(2) Å and 1.485(8) Å, respectively, and the Ra–O–S bond angle was 127(2)∘. Findings of EXAFS data are quite consistent and support the XRD data. These findings show that it is possible for radium to coprecipitate with barium, strontium, and lead in sulphate media to form a substitutional solid solution.

Preparation and characterization of a novel solid solution of aluminum in tungsten carbide by mechanically activated high-temperature reaction

2006 ◽  
Vol 21 (7) ◽  
pp. 1700-1703 ◽  
Author(s):  
Junmin Yan ◽  
Xianfeng Ma ◽  
Wei Zhao ◽  
Huaguo Tang ◽  
Changjun Zhu ◽  
...  
Keyword(s):  
Solid Solution ◽  
High Temperature ◽  
Substitutional Solid Solution ◽  
Phase Identification ◽  
Temperature Reaction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cell Parameters ◽  
High Temperature Reaction

In this work, a novel substitutional solid solution (W0.8Al0.2)C was synthesized by mechanically activated high-temperature reaction. X-ray diffraction was used for phase identification during the whole reaction process. Environment scanning electronic microscopy–field emission gun and energy dispersive x-ray were used to investigate the microstructure and the quantitative material composition of the specimen. (W0.8Al0.2)C was found to crystallize in the WC-type, and the cell parameters were a = 2.907(1) Å and c = 2.837(1) Å. The hardness of (W0.8Al0.2)C was tested to be 19.3 ± 1 GPa, and the density was 13.19 ± 0.05 g cm−3.

scholarly journals Crystallization, optimization and preliminary X-ray characterization of a metal-dependent PI-PLC fromStreptomyces antibioticus

2012 ◽  
Vol 68 (11) ◽  
pp. 1378-1386 ◽  
Author(s):  
Michael R. Jackson ◽  
Thomas L. Selby
Keyword(s):  
X Ray Diffraction ◽  
Hanging Drop ◽  
Orthorhombic Space Group ◽  
X Ray ◽  
Streptomyces Antibioticus ◽  
Cell Parameters ◽  
Heavy Atoms ◽  
Hanging Drop Method

A recombinant metal-dependent phosphatidylinositol-specific phospholipase C (PI-PLC) fromStreptomyces antibioticushas been crystallized by the hanging-drop method with and without heavy metals. The native crystals belonged to the orthorhombic space groupP222, with unit-cell parametersa= 41.26,b= 51.86,c = 154.78 Å. The X-ray diffraction results showed significant differences in the crystal quality of samples soaked with heavy atoms. Additionally, drop pinning, which increases the surface area of the drops, was also used to improve crystal growth and quality. The combination of heavy-metal soaks and drop pinning was found to be critical for producing high-quality crystals that diffracted to 1.23 Å resolution.

The structures of marialite (Me6) and meionite (Me93) in space groups P42/n and I4/m, and the absence of phase transitions in the scapolite series

2011 ◽  
Vol 26 (2) ◽  
pp. 119-125 ◽  
Author(s):  
Sytle M. Antao ◽  
Ishmael Hassan
Keyword(s):  
Phase Transitions ◽  
High Resolution ◽  
Crystal Structures ◽  
Unit Cell ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Space Groups ◽  
Cell Parameters ◽  
The Mean

The crystal structures of marialite (Me6) from Badakhshan, Afghanistan and meionite (Me93) from Mt. Vesuvius, Italy were obtained using synchrotron high-resolution powder X-ray diffraction (HRPXRD) data and Rietveld structure refinements. Their structures were refined in space groups I4/m and P42/n, and similar results were obtained. The Me6 sample has a formula Ca0.24Na3.37K0.24[Al3.16Si8.84O24]Cl0.84(CO3)0.15, and its unit-cell parameters are a=12.047555(7), c=7.563210(6) Å, and V=1097.751(1) Å3. The average ⟨T1-O⟩ distances are 1.599(1) Å in I4/m and 1.600(2) Å in P42/n, indicating that the T1 site contains only Si atoms. In P42/n, the average distances of ⟨T2-O⟩=1.655(2) and ⟨T3-O⟩=1.664(2) Å are distinct and are not equal to each other. However, the mean ⟨T2,3-O⟩=1.659(2) Å in P42/n and is identical to the ⟨T2′-O⟩=1.659(1) Å in I4/m. The ⟨M-O⟩ [7]=2.754(1) Å (M site is coordinated to seven framework O atoms) and M-A=2.914(1) Å; these distances are identical in both space groups. The Me93 sample has a formula of Na0.29Ca3.76[Al5.54Si6.46O24]Cl0.05(SO4)0.02(CO3)0.93, and its unit-cell parameters are a=12.19882(1), c=7.576954(8) Å, and V=1127.535(2) Å3. A similar examination of the Me93 sample also shows that both space groups give similar results; however, the C–O distance is more reasonable in P42/n than in I4/m. Refining the scapolite structure near Me0 or Me100 in I4/m forces the T2 and T3 sites (both with multiplicity 8 in P42/n) to be equivalent and form the T2′ site (with multiplicity 16 in I4/m), but ⟨T2-O⟩ is not equal to ⟨T3-O⟩ in P42/n. Using different space groups for different regions across the series implies phase transitions, which do not occur in the scapolite series.

Characterization of Ni Nanopowders Produced by Electrical Explosion of Wire Technique

2006 ◽  
Vol 510-511 ◽  
pp. 710-713
Author(s):  
Hwan Tae Kim ◽  
Won Sik Seo ◽  
Dae Hwan Kwon ◽  
Pyuck Pa Choi ◽  
Ji Soon Kim ◽  
...  
Keyword(s):  
Particle Size ◽  
Electrical Explosion ◽  
Nickel Wire ◽  
X Ray Diffraction ◽  
Nitrogen Gas ◽  
Argon Gas ◽  
X Ray ◽  
Nickel Powders ◽  
The Mean

Nanosize nickel powders were successfully produced by electrical explosion of wire (EEW). In EEW, the nickel wire was discharged in a chamber filled with nitrogen or argon gas, and the produced powders were subsequently stabilized by air-passivation at room temperature for 2 h. X-ray diffraction only showed the nickel phase of FCC crystal structure, whereas TEM and XPS analyses showed the formation of a very thin oxide layer of NiO on the surface of particles. Particles were spherical in shape, and the mean particle size calculated by specific surface area was about 100 nm. The particle size decreased with increasing charging voltage and with increasing ambient gas pressure. Argon gas was more effective in producing finer particles than nitrogen gas.

scholarly journals Growth and Characterization of Pure and Doped L-Alanine Tartrate Single Crystals

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
K. Rajesh ◽  
B. Milton Boaz ◽  
P. Praveen Kumar
Keyword(s):  
Single Crystals ◽  
Vickers Microhardness ◽  
Diffraction Method ◽  
Dielectric Studies ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cell Parameters ◽  
Ft Ir ◽  
Ft Ir Spectroscopy

Single crystals of pure and Lanthanum doped L-Alanine Tartrate were grown by slow evaporation method. The cell parameters were determined using single crystal X-ray diffraction method. To improve the physical properties of the LAT crystal, Lanthanum dopant was added by 2 mol%. ICP studies confirm the presence of Lanthanum in the grown LAT crystal. Transparency range of the crystal was determined using UV-VIS-NIR spectrophotometer. The functional groups of pure and doped LAT crystals were analyzed by FT-IR spectroscopy. Using Vickers microhardness tester, mechanical strength of the material was found. Dielectric studies of pure and doped LAT single crystals were carried out. The doped LAT crystal is found to have efficiency higher than that of pure LAT crystal.

Preparation and Characterization of Nanosized Barium-Strontium Titanate Immobilized on Aluminum Oxide and its Application in Separation of Cr(III) and Cr(VI)

2010 ◽  
Vol 152-153 ◽  
pp. 1013-1016
Author(s):  
Hong Wang ◽  
Jing Yang
Keyword(s):  
Aluminum Oxide ◽  
Strontium Titanate ◽  
Barium Strontium Titanate ◽  
Sol Gel ◽  
Complete Separation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ph Values ◽  
Barium Strontium

Nanometer barium-strontium titanate based coated aluminum oxide (ABST) was prepared by the sol–gel method and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared spectrophotometry (FTIR). Its application in speciation of Cr(III) and Cr(VI) from water were studied. The results showed that the nanometer barium-strontium titanate was immobilized on aluminum oxide firmly, becoming a new adsorbent. Two forms of chromium showed different exchange capacities at different pH values, viz. Cr (III) selectively retained at pH 10–13, whereas Cr (VI) retained at pH 1. Hence complete separation of the two forms of chromium is possible. Retained species were eluted with 5mL of 1 mol•L−1 HCl and 1 mol•L−1 NaOH. The Cr(III) and Cr(VI) concentration was measured by atomic absorption spectroscopy. The adsorbent had a promising prospect in the separation of Cr(III) and Cr(VI) in environment water.

Synthesis and Characterization of Surface Protected Nanocrystalline Particles of Titania

1998 ◽  
Vol 519 ◽  
Author(s):  
E. Scolan ◽  
C. Sanchez
Keyword(s):  
X Ray Diffraction ◽  
Elastic Light Scattering ◽  
Titanium Butoxide ◽  
X Ray ◽  
Toluene Sulfonic Acid ◽  
Nanocrystalline Particles ◽  
Mean Size ◽  
The Mean ◽  
Cp Mas Nmr

AbstractMonodisperse non-aggregated nanoparticles of titania are obtained through hydrolysis at 60°C of titanium butoxide in the presence of acetylacetone and para-toluene sulfonic acid. After drying the resulting xerosols can be dispersed without aggregation in water-alcoholic or alcoholic solutions. The characterizations of the nanoparticles have been carried out by using quasi-elastic light scattering (QELS), 13C 1H in solution and X-ray diffraction, TEM, TG-DTA, 13C CP-MAS NMR in the solid state. The mean size of the anatase oxide core can be adjusted in the I to 5 nanometer range by a careful tuning of the synthetic conditions. The anatase particles are surrounded by acetylacetonato ligands, para-toluene sulfonate based species and water.

Preparation and Characterization of Lignin Powder Micronized by a Supercritical Antisolvent (SAS) Process

2011 ◽  
Vol 233-235 ◽  
pp. 1642-1645 ◽  
Author(s):  
Qi Lu ◽  
Yuan Gang Zu ◽  
Lei Yang ◽  
Xiu Hua Zhao ◽  
Wen Jun Liu ◽  
...  
Keyword(s):  
Particle Size ◽  
Optimal Conditions ◽  
Orthogonal Array Design ◽  
X Ray Diffraction ◽  
Array Design ◽  
X Ray ◽  
Mean Particle Size ◽  
Supercritical Antisolvent ◽  
The Mean

Nanoscale lignin was successfully prepared with a supercritical antisolvent (SAS) apparatus using acetone as a solvent and superciritical carbon dioxide as an antisolvent. Four factors were studied and optimized by a four-level orthogonal array design (OAD). According to analysis of variance, precipitation pressure had a significant effect on mean particle size. The optimal conditions are as follows: precipitation temperature 35 °C, precipitation pressure 30 MPa, temperature difference +10 °C and concentration of lignin solution 0.5 mg/mL. The micronized lignin under the optimal conditions was characterized by Scanning Electron Microscopy (SEM), Fourier-transform Infrared Spectroscopy (FTIR), Dynamic Light Scattering (DLS) and X-Ray Diffraction (XRD) analyses. The results showed the mean particle size of micronized lignin was 0.144 ± 0.03 μm and had no degradation. The solubility of micronized lignin was improved significantly in distilled water.

scholarly journals Purification and X-ray crystallographic analysis of 7-keto-8-aminopelargonic acid (KAPA) synthase fromMycobacterium smegmatis

2014 ◽  
Vol 70 (10) ◽  
pp. 1372-1375 ◽  
Author(s):  
Shanghua Fan ◽  
Defeng Li ◽  
Joy Fleming ◽  
Yuan Hong ◽  
Tao Chen ◽  
...  
Keyword(s):  
Crystallographic Analysis ◽  
Unit Cell ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters ◽  
Essential Enzyme ◽  
Mycobacterial Growth

7-Keto-8-aminopelargonic acid synthase (KAPA synthase; BioF) is an essential enzyme for mycobacterial growth that catalyses the first committed step in the biotin-synthesis pathway. It is a pyridoxal 5′-phosphate (PLP)-dependent enzyme and is a potential drug target. Here, the cloning, expression, purification and crystallization of KAPA synthase fromMycobacterium smegmatis(MsBioF) and the characterization of MsBioF crystals using X-ray diffraction are described. The crystals diffracted to 2.3 Å resolution and belonged to the monoclinic space groupP21, with unit-cell parametersa= 70.88,b= 91.68,c= 109.84 Å, β = 97.8°. According to the molecular weight of MsBioF, the unit-cell parameters and the self-rotation function map, four molecules are present in each asymmetric unit with aVMvalue of 2.06 Å3 Da−1and a solvent content of 40.20%.

scholarly journals Synthesis, Spectroscopic and X-Ray Structural Characterization of [Cd(linpen)]2+, a Model for Metal Complexes of the Chelating Polymer Polyethyleneimine (linpen = Linear Pentaethylenehexamine)

1992 ◽  
Vol 47 (6) ◽  
pp. 829-836 ◽  
Author(s):  
Henry Strasdeit
Keyword(s):  
Metal Ion ◽  
X Ray Diffraction ◽  
Linear Isomer ◽  
X Ray ◽  
Chelating Polymer ◽  
The Mean ◽  
Hexadentate Ligand ◽  
Solid Compounds ◽  
Strong Distortion

The isolation of 3,6,9,12-tetraazatetradecane-1,14-diamine (linear isomer of pentaethylenehexamine, linpen) from a technical polyamine mixture is described. In methanol, linpen acts as a hexadentate ligand towards cadmium(II). The solid compounds [Cd(linpen)](BPh4)2 (1), [Cd(linpen)](BPh4)2•2 DMSO (2) and [Cd(linpen)](BF4)2 (3) have been isolated and characterized by elemental analysis, spectroscopy and X-ray powder diffraction. The 113Cd NMR resonance of 1 is at 351 ppm (0.30 M in DMSO-d6, standard: 0.10 M Cd(ClO4)2 in D2O).2 and 3 have been structurally characterized by single-crystal X-ray diffraction. 2: C 2/c; a = 19.337(1)Å, b = 17.937(1)Å, c = 18.584(1)Å, β = 111.54(1)°; Z = 4, R = 0.034, Rw = 0.033.3: P21/n; a = 8.607(1)Å, b = 14.851(2)Å, c = 15.703(2)Å, ß = 91.21(2)°; Z = 4,R = 0.083, Rw = 0.072. Both compounds contain discrete [Cd(linpen)]2+ complexes. The hexamine wraps around the metal ion in a helical manner. This results in a strong distortion of the coordination polyhedron. The mean Cd-N bond lengths are 2.38Å and 2.37Å for 2 and 3, respectively.Models for MN6 centers in metal-polyethyleneimine (PEI) complexes are derived from the structure of [Cd(linpen)]2+. For example, loops at the MN6 site in molecules of linear PEI are proposed.

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