X-Ray Diffraction Analysis of Barium-Strontium Sulfate (Barite-Celestite) Solid Solutions

1989 ◽  
Vol 4 (4) ◽  
pp. 214-216 ◽  
Author(s):  
Elihu Goldish

AbstractCrystal data are given for synthetic mixed bariumstrontium sulfates, and a powder pattern for (Ba0.50Sr0.50)SO4 is presented. Taken with previously published data for the end-member sulfates, we verify the nonlinear behavior of the unit-cell edges with composition, and present tables of interpolated data from which d-spacings for intermediate compositions can be calculated. The use of these data for analysis of complex natural samples by use of the 121 peak is described.

Open Physics ◽  
2012 ◽  
Vol 10 (1) ◽  
Author(s):  
Ludmila Sevastyanova ◽  
Olga Gulish ◽  
Vladimir Stupnikov ◽  
Vladimir Genchel ◽  
Oleg Kravchenko ◽  
...  

AbstractCompounds with the general formula Mg1−x AlxB2 were obtained by two-step ceramic synthesis. All compounds were characterized by X-ray diffraction, NMR spectroscopy, and by four point probe resistivity measurements in various magnetic fields method. The diborides unit cell parameters were determined as a function of the Al mole fraction. With the vaues of x up to 0.40 (where x is the composition of the stock prepared for sintering), the unit cell parameters of Mg1−x AlxB2 are similar to those of pure MgB2 and the superconducting transition temperature was lowered. For stock compositions of 0:25 ≤ x ≤ 0:60, the products contain a superstructure, also superconducting phase, which becomes the only product at x = 0:50, and at x > 0:60 this phase is replaced by AlB2-based solid solutions.


2019 ◽  
Vol 64 (2) ◽  
pp. 266-269
Author(s):  
A. U. Sheleg ◽  
V. F. Gremenok ◽  
A. S. Sereda ◽  
V. G. Hurtavy ◽  
V. A. Chumak ◽  
...  

2003 ◽  
Vol 18 (3) ◽  
pp. 236-239 ◽  
Author(s):  
L. Marosi ◽  
J. Cifré ◽  
C. Otero Areán

The new heteropoly blue compound (MoO2)0.5PMo14O42, which is relevant in the context of catalytic activity of heteropoly-molybdates, was prepared by controlled thermolysis of (NH4)3PMo12O40 at 730 K in a nitrogen atmosphere. Powder X-ray diffraction analysis showed that this compound has a cubic unit cell, space group Pn3m (No. 224), with ao=11.795(2) Å, Z=2 and DXR=4.2466 g cm−3. Computer modeling and Rietveld analysis of powder diffraction patterns led to a proposed structure of the corresponding Keggin-cage unit PMo14O42.


1999 ◽  
Vol 14 (3) ◽  
pp. 231-233 ◽  
Author(s):  
Raj P. Singh ◽  
Michael J. Miller ◽  
Jeffrey N. Dann

(Na0.6H0.4)(Ta0.7Nb0.3)O3 was synthesized by heating a tantalum/niobium scale containing two sodium tantalate/niobate phases :Na14(Ta0.7Nb0.3)12O37·31H2O and NaH2Ta0.7Nb0.3O4. Powder X-ray diffraction data for (Na0.6H0.4)(Ta0.7Nb0.3)O3 indicated it to be a cubic perovskite (ABO3/ReO3 type structure) with unit cell a0=3.894 Å. The compound is analogous to the mineral lueshite (NaNbO3), and to the high temperature forms of NaTaO3 and NaNbO3. Powder diffraction data for (Na0.6H0.4)(Ta0.7Nb0.3)O3 will be useful in the analysis of synthetic tantalum/niobium concentrates.


Author(s):  
Jintang Lei ◽  
Xun Cai ◽  
Xiaodan Ma ◽  
Li Zhang ◽  
Yuwen Li ◽  
...  

The Bam machinery, which is highly conserved from bacteria to humans, is well recognized as the apparatus responsible for the insertion and folding of most outer membrane proteins in Gram-negative bacteria. InEscherichia coli, the Bam machinery consists of five components (i.e.BamA, BamB, BamC, BamD and BamE). In comparison, there are only four partners inHaemophilus influenzae: a BamB homologue is not found in its genome. In this study, the recombinant expression, purification, crystallization and preliminary X-ray diffraction analysis ofH. influenzaeBamD and BamCD complex are reported. The genes encoding BamC and BamD were cloned into a pET vector and expressed inE. coli. Affinity, ion-exchange and gel-filtration chromatography were used to obtain high-purity protein for further crystallographic characterization. Using the hanging-drop vapour-diffusion technique, BamD and BamCD protein crystals of suitable size were obtained using protein concentrations of 70 and 50 mg ml−1, respectively. Preliminary X-ray diffraction analysis showed that the BamD crystals diffracted to 4.0 Å resolution and belonged to space groupP212121, with unit-cell parametersa= 54.5,b= 130.5,c= 154.7 Å. The BamCD crystals diffracted to 3.8 Å resolution and belonged to space groupI212121, with unit-cell parametersa= 101.6,b= 114.1,c= 234.9 Å.


1973 ◽  
Vol 17 ◽  
pp. 20-31
Author(s):  
Howard F. McMurdie

AbstractThe identification of crystalline phases by x-ray diffraction, either by powder or single crystal techniques requires a dependable body of reference data. It is not only necessary to have data on each phase which are accurate and complete, it also is desirable to have data on as wide a range of compounds as possible, and to have the data organized in such a manner as to be readily usable. The outstanding compilations which approach these goals are the Powder Diffraction File and Crystal Data.The Powder Diffraction File, published by the Joint Committee on Powder Diffraction Standards has data covering about 22,500 phases, both organic and inorganic. These data are of various degrees of accuracy as is indicated by symbols. The File is continuously being improved by the addition of evaluated data from the general literature and by data produced by supporting projects, the principal one being the Joint Committee Associateship at the National Bureau of Standards.To be noted in the File with a star, and to be truly considered standard data a powder pattern must be complete in the sense of including all reflections above the minimum “d” spacing covered, both weak lines and those with large “d” spacings. Since the best test of a pattern is its own internal consistency, the reflections must all have hkl's assigned and must show a good agreement between the spacings observed and those calculated from a refined cell, and they must be consistent with the known space group. This agreement can be best obtained by the use of an internal standard and a computer program. The intensities should be measured by a method which minimizes the effect of crystal orientation.The PDF is provided with search procedure manuals arranged on a scheme of the strongest lines to help in locating data matching that from an unknovm. A computer program for rapid searching is available. A recent development is the inclusion of a “reference intensity” to aid in estimating the quantitative analysis of mixtures.Crystal Data is a compilation now in the third edition made at the National Bureau of Standards and published by the Joint Committee on Powder Diffraction Standards. It contains data on the unit cell parameters of over 24,000 phases. These data are arranged by crystal system and axial ratios to simplify identification of phases from unit cell data obtained from Single crystal cameras.Both of these large compilations are also important reference sources for crystallographic information giving structural information and literature references.


1999 ◽  
Vol 55 (5) ◽  
pp. 721-725 ◽  
Author(s):  
Mitsuko Onoda ◽  
Xue-An Chen ◽  
Katsuo Kato ◽  
Akira Sato ◽  
Hiroaki Wada

The structure of the orthorhombic room-temperature phase of Cu8GeS6 (copper germanium sulfide), Mr = 773.27, has been refined on the basis of X-ray diffraction data from a 12-fold twinned crystal applying a six-dimensional twin refinement technique. For 1804 unique reflections measured using Mo Kα radiation, RF was 0.083 with 77 structure parameters and 12 scale factors. The symmetry operations, the unit cell and other crystal data are (0, 0, 0; ½, ½, 0) + x, y, z; y, x, z; ¼ − x, ¾ − y, ½ + z; ¾ − y, ¼ − x, ½ + z; a = b = 9.9073 (3) Å, c = 9.8703 (4) Å, α = β = 90°, γ = 90.642 (4)°; V = 968.7 (1) Å3, Z = 4, Dx  = 5.358 Mg m−3, μ = 21.70 mm−1. The standard setting of the space group and the reduced unit cell are Pmn21; a = 7.0445 (3), b = 6.9661 (3), c = 9.8699 (5) Å; Z = 2.


2014 ◽  
Vol 70 (10) ◽  
pp. 1389-1393 ◽  
Author(s):  
Mulu Y. Lubula ◽  
Amanda Poplawaski ◽  
Karen C. Glass

The bromodomain-PHD finger protein 1 (BRPF1) is an essential subunit of the monocytic leukemia zinc (MOZ) histone acetyltransferase (HAT) complex and is required for complex formation and enzymatic activation. BRPF1 contains a structurally conserved bromodomain, which recognizes specific acetyllysine residues on histone proteins. The MOZ HAT plays a direct role in hematopoiesis, and deregulation of its activity is linked to the development of acute myeloid leukemia. However, the molecular mechanism of histone-ligand recognition by the BRPF1 bromodomain is currently unknown. The 117-amino-acid BRPF1 bromodomain was overexpressed inEscherichia coliand purified to homogeneity. Crystallization experiments of the BRPF1 bromodomain in complex with its H4K12ac and H2AK5ac histone ligands yielded crystals that were suitable for high-resolution X-ray diffraction analysis. The BRPF1 bromodomain–H4K12ac crystals belonged to the tetragonal space groupP43212, with unit-cell parametersa= 75.1,b= 75.1,c= 86.3 Å, and diffracted to a resolution of 1.94 Å. The BRPF1 bromodomain–H2AK5ac crystals grew in the monoclinic space groupP21, with unit-cell parametersa= 60.9,b= 55.6,c= 82.1 Å, β = 93.6°, and diffracted to a resolution of 1.80 Å. Complete data sets were collected from both crystal forms using synchrotron radiation on beamline X29 at Brookhaven National Laboratory (BNL).


2014 ◽  
Vol 70 (10) ◽  
pp. 1398-1401 ◽  
Author(s):  
Masahiro Nakajima ◽  
Ryuta Yoshida ◽  
Akimasa Miyanaga ◽  
Hayao Taguchi

Lin1840 is a putative β-glucosidase that is predicted to be involved in 1,2-β-glucan metabolism since thelin1839gene encoding a 1,2-β-oligoglucan phosphorylase and thelin1840gene are located in the same gene cluster. Here, Lin1840 was crystallized. The crystals of Lin1840 diffracted to beyond 1.8 Å resolution. The crystal belonged to space groupI121, with unit-cell parametersa= 89.75,b= 95.10,c= 215.00 Å, α = 90.00, β = 96.34, γ = 90.00°.


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