scholarly journals “Mohsite” of Colomba: Identification as Dessauite-(Y)

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Erica Bittarello ◽  
Marco E. Ciriotti ◽  
Emanuele Costa ◽  
Lorenzo Mariano Gallo
Keyword(s):  
Equivalent Material ◽  
Crystal Chemical Formula ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters ◽  
Eds Analysis ◽  
Microraman Spectroscopy ◽  
French Region ◽  
Historical Samples

During a reorganization of the mineralogical collection of Turin University, old samples of the so-called mohsite of Colomba were found. “Mohsite” was discredited in 1979 by Kelly et al., as a result of some analyses performed on the equivalent material coming from the French region of Hautes-Alpes, but the original samples found in similar geological setting in Italy were lost and never analysed with modern equipment. After more than a century, the rediscovered samples of Professor Colomba were analysed by means of SEM-EDS analysis, microRaman spectroscopy, and X-ray diffraction. The results have demonstrated that the historical samples studied by Colomba are Pb-free dessauite-(Y), and pointed to an idealized crystal chemical formula (Sr0.70Na0.25Ca0.09)Σ=1.04 (Y0.62U0.18Yb0.09Sc0.08)Σ=0.97  Fe22+(Ti12.66Fe4.783+V0.263+)Σ=17.70O38 and unit-cell parameters a = 10.376(3) Å, c = 20.903(6) Å, and V = 1949(1) Å3.

Crystal Chemistry of Zemannite-Type Structures: III. Keystoneite, the Ni2+-Analogue of Zemannite, and Ferrotellurite Discredited

2021 ◽  
Author(s):  
Owen P. Missen ◽  
Malcolm E. Back ◽  
Stuart J. Mills ◽  
Andrew C. Roberts ◽  
Yvon LePage ◽  
...  
Keyword(s):  
Full Description ◽  
Electron Probe Micro Analysis ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters ◽  
Boulder County ◽  
Micro Analysis ◽  
Historical Samples ◽  
The Ideal

ABSTRACT Keystoneite (IMA87–049) is a tellurite mineral from the Keystone mine, Magnolia District, Boulder County, Colorado, USA. In this paper the first full description of keystoneite is presented. Keystoneite is the Ni2+ analogue of zemannite and has the ideal zemannite-like formula of Mg0.5Ni2+Fe3+(Te4+O3)3·4H2O. The chemical composition via electron-probe micro-analysis (in wt.%; standard deviations in brackets) is Na2O 0.3 (0.2), K2O 0.1 (0.0), MgO 4.3 (0.3), Mn2O3 1.1 (0.7), Fe2O3 5.1 (1.2), NiO 12.7 (1.7), and TeO2 65.5 (0.7). H2O was determined by TGA analysis, giving 15(3) wt.% H2O, however, H2O from the structural determination gave 10.0 wt.%, the latter giving an analytical total of 99.1 wt.%. Keystoneite crystallizes in the non-centrosymmetric space group P63. The six strongest observed powder-diffraction lines [d,Å(I)(hkl)] are 8.12(90)(100), 4.05(80)(200), 2.952(50)(112), 2.838(50)(121,211), 2.774(100)(202), and 1.720(60)(204). The unit-cell parameters determined from single-crystal X-ray diffraction are a = 9.3667(5) Å, c = 7.6173(3) Å, V = 578.77(6) Å3, and Z = 2. Keystoneite was first identified from a specimen of “ferrotellurite”, a mineral with the reported formula Fe2+Te6+O4. The discreditation of “ferrotellurite” has been accepted by the IMA-CNMNC, Proposal 19-G, as no material corresponding to a phase remotely similar to Fe2+Te6+O4 was found on any historical samples labelled as containing “ferrotellurite”.

Structural Study of a new Compound Based on Acid 1,4-Cyclohexanedicarboxylic (1,4-CDC)

2010 ◽  
Vol 6 (1) ◽  
pp. 891-896
Author(s):  
Manel Halouani ◽  
M. Dammak ◽  
N. Audebrand ◽  
L. Ktari
Keyword(s):  
Aqueous Solution ◽  
Water Molecules ◽  
Carboxyl Group ◽  
X Ray Diffraction ◽  
Compound I ◽  
Unit Cell Parameters ◽  
Monoclinic System ◽  
X Ray ◽  
Cell Parameters ◽  
Cyclohexanedicarboxylic Acid

One nickel 1,4-cyclohexanedicarboxylate coordination polymers, Ni2 [(O10C6H4)(COO)2].2H2O  (I), was hydrothermally synthesized from an aqueous solution of Ni (NO3)2.6H2O, (1,4-CDC) (1,4-CDC = 1,4-cyclohexanedicarboxylic acid) and tetramethylammonium nitrate. Compound (I) crystallizes in the monoclinic system with the C2/m space group. The unit cell parameters are a = 20.1160 (16) Å, b = 9.9387 (10) Å, c = 6.3672 (6) Å, β = 97.007 (3) (°), V= 1263.5 (2) (Å3) and Dx= 1.751g/cm3. The refinement converged into R= 0.036 and RW = 0.092. The structure, determined by single crystal X-ray diffraction, consists of two nickel atoms Ni (1) and Ni (2). Lots of ways of which is surrounded by six oxygen atoms, a carboxyl group and two water molecules.

scholarly journals Crystallization and preliminary X-ray diffraction analysis of the Csu pili CsuC–CsuA/B chaperone–major subunit pre-assembly complex fromAcinetobacter baumannii

2015 ◽  
Vol 71 (6) ◽  
pp. 770-774 ◽  
Author(s):  
Natalia Pakharukova ◽  
Minna Tuittila ◽  
Sari Paavilainen ◽  
Anton Zavialov
Keyword(s):  
Diffusion Method ◽  
X Ray Diffraction ◽  
Hanging Drop ◽  
Unit Cell Parameters ◽  
Gram Negative ◽  
X Ray ◽  
Cell Parameters ◽  
Abiotic Surfaces ◽  
Vapour Diffusion ◽  
Fimbrial Adhesins

The attachment of many Gram-negative pathogens to biotic and abiotic surfaces is mediated by fimbrial adhesins, which are assembledviathe classical, alternative and archaic chaperone–usher (CU) pathways. The archaic CU fimbrial adhesins have the widest phylogenetic distribution, yet very little is known about their structure and mechanism of assembly. To elucidate the biogenesis of archaic CU systems, structural analysis of the Csu fimbriae, which are used byAcinetobacter baumanniito form stable biofilms and cause nosocomial infection, was focused on. The major fimbriae subunit CsuA/B complexed with the CsuC chaperone was purified from the periplasm ofEscherichia colicells co-expressing CsuA/B and CsuC, and the complex was crystallized in PEG 3350 solution using the hanging-drop vapour-diffusion method. Selenomethionine-labelled CsuC–CsuA/B complex was purified and crystallized under the same conditions. The crystals diffracted to 2.40 Å resolution and belonged to the hexagonal space groupP6422, with unit-cell parametersa=b= 94.71,c = 187.05 Å, α = β = 90, γ = 120°. Initial phases were derived from a single anomalous diffraction (SAD) experiment using the selenomethionine derivative.

Silicate-germanate K2Y[(Si3Ge)O10(OH)] with unusual complex corrugated layer and its correlation to ring silicate gerenite and chain silicate chkalovite

2020 ◽  
Vol 235 (4-5) ◽  
pp. 167-172
Author(s):  
Anastasiia P. Topnikova ◽  
Elena L. Belokoneva ◽  
Olga V. Dimitrova ◽  
Anatoly S. Volkov ◽  
Leokadiya V. Zorina
Keyword(s):  
Low Temperature ◽  
Cross Section ◽  
Complex Anion ◽  
Diffraction Experiment ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters ◽  
Chain Silicate ◽  
Novel Complex

AbstractA new silicate-germanate K2Y[(Si3Ge)O10(OH)] was synthesized hydrothermally in a system Y2O3:GeO2:SiO2 = 1:1:2 (T = 280 °C; P = 90–100 atm.); K2CO3 was added to the solution as a mineralizer. Single-crystal X-ray diffraction experiment was carried out at low temperature (150 K). The unit cell parameters are a = 10.4975(4), b = 6.9567(2), c = 15.4001(6) Å, β = 104.894(4)°; V = 1086.86(7) Å3; space group is P 21/c. A novel complex anion is presented by corrugated (Si,Ge) tetrahedral layers connected by couples of YO6 octahedra into the mixed microporous framework with the channels along b and a axes, the maximal size of cross-section is ~5.6 Å. This structure has similarity with the two minerals: ring silicate gerenite (Ca,Na)2(Y,REE)3Si6O18 · 2H2O and chain silicate chkalovite Na2BeSi2O6. Six-member rings with 1̅ symmetry as in gerenite are distinguished in the new layer. They are mutually perpendicular to each other and connected by additional tetrahedra. Straight crossing chains in chkalovite change to zigzag four-link chains in the new silicate-germanate layer.

X-ray powder diffraction data of LaNi0.5Ti0.45Co0.05O3, LaNi0.45Co0.05Ti0.5O3, and LaNi0.5Ti0.5O3 perovskites

2021 ◽  
pp. 1-6
Author(s):  
Mariana M. V. M. Souza ◽  
Alex Maza ◽  
Pablo V. Tuza
Keyword(s):  
Crystal Structure ◽  
Rietveld Method ◽  
Pechini Method ◽  
Powder Diffraction Data ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters ◽  
Modified Pechini Method ◽  
Scanning Electron

In the present work, LaNi0.5Ti0.45Co0.05O3, LaNi0.45Co0.05Ti0.5O3, and LaNi0.5Ti0.5O3 perovskites were synthesized by the modified Pechini method. These materials were characterized using X-ray fluorescence, scanning electron microscopy, and powder X-ray diffraction coupled to the Rietveld method. The crystal structure of these materials is orthorhombic, with space group Pbnm (No 62). The unit-cell parameters are a = 5.535(5) Å, b = 5.527(3) Å, c = 7.819(7) Å, V = 239.2(3) Å3, for the LaNi0.5Ti0.45Co0.05O3, a = 5.538(6) Å, b = 5.528(4) Å, c = 7.825(10) Å, V = 239.5(4) Å3, for the LaNi0.45Co0.05Ti0.5O3, and a = 5.540(2) Å, b = 5.5334(15) Å, c = 7.834(3) Å, V = 240.2(1) Å3, for the LaNi0.5Ti0.5O3.

scholarly journals Crystal Structure Refinements of Four Monazite Samples from Different Localities

Minerals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1028 ◽  
Author(s):  
M. Mashrur Zaman ◽  
Sytle M. Antao
Keyword(s):  
Crystal Structure ◽  
Electron Probe ◽  
Unit Cell Volume ◽  
Unit Cell ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters ◽  
Large Unit Cell ◽  
A Site

This study investigates the crystal chemistry of monazite (APO4, where A = Lanthanides = Ln, as well as Y, Th, U, Ca, and Pb) based on four samples from different localities using single-crystal X-ray diffraction and electron-probe microanalysis. The crystal structure of all four samples are well refined, as indicated by their refinement statistics. Relatively large unit-cell parameters (a = 6.7640(5), b = 6.9850(4), c = 6.4500(3) Å, β = 103.584(2)°, and V = 296.22(3) Å3) are obtained for a detrital monazite-Ce from Cox’s Bazar, Bangladesh. Sm-rich monazite from Gunnison County, Colorado, USA, has smaller unit-cell parameters (a = 6.7010(4), b = 6.9080(4), c = 6.4300(4) Å, β = 103.817(3)°, and V = 289.04(3) Å3). The a, b, and c unit-cell parameters vary linearly with the unit-cell volume, V. The change in the a parameter is large (0.2 Å) and is related to the type of cations occupying the A site. The average <A-O> distances vary linearly with V, whereas the average <P-O> distances are nearly constant because the PO4 group is a rigid tetrahedron.

scholarly journals Synthesis, purification and crystallographic studies of the C-terminal sterol carrier protein type 2 (SCP-2) domain of human hydroxysteroid dehydrogenase-like protein 2

2015 ◽  
Vol 71 (7) ◽  
pp. 901-905 ◽  
Author(s):  
Zhong Cheng ◽  
Yao Li ◽  
Chun Sui ◽  
Xiaobo Sun ◽  
Yong Xie
Keyword(s):  
Catalytic Domain ◽  
Hydroxysteroid Dehydrogenase ◽  
Carrier Protein ◽  
Sterol Carrier Protein ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters ◽  
Protein Molecules

Human hydroxysteroid dehydrogenase-like protein 2 (HSDL2) is a member of the short-chain dehydrogenase/reductase (SDR) subfamily of oxidoreductases and contains an N-terminal catalytic domain and a C-termianl sterol carrier protein type 2 (SCP-2) domain. In this study, the C-terminal SCP-2 domain of human HSDL2, including residues Lys318–Arg416, was produced inEscherichia coli, purified and crystallized. X-ray diffraction data were collected to 2.10 Å resolution. The crystal belonged to the trigonal space groupP3121 (orP3221), with unit-cell parametersa=b= 70.4,c= 60.6 Å, α = β = 90, γ = 120°. Two protein molecules are present in the asymmetric unit, resulting in a Matthews coefficient of 2.16 Å3 Da−1and an approximate solvent content of 43%.

Refinement of the crystal structure of sieleckiite and revision of its symmetry

2017 ◽  
Vol 81 (4) ◽  
pp. 917-922
Author(s):  
Peter Elliott
Keyword(s):  
Crystal Structure ◽  
Synchrotron Radiation ◽  
Single Crystal ◽  
Diffraction Data ◽  
X Ray Diffraction ◽  
Aluminium Phosphate ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters ◽  
Phosphate Mineral

AbstractThe crystal structure of the copper aluminium phosphate mineral sieleckiite, Cu3Al4(PO4)2 (OH)12·2H2O, from the Mt Oxide copper mine, Queensland, Australia was solved from single-crystal X-ray diffraction data utilizing synchrotron radiation. Sieleckiite has monoclinic rather than triclinic symmetry as previously reported and is space group C2/m with unit-cell parameters a = 11.711(2), b = 6.9233(14), c = 9.828(2) Å, β = 92.88(3)°, V = 795.8(3) Å3and Z = 2. The crystal structure, which has been refined to R1 = 0.0456 on the basis of 1186 unique reflections with Fo > 4σF, is a framework of corner-, edge- and face- sharing Cu and Al octahedra and PO4 tetrahedra.

Compressibility of β-As4S4: an in situ high-pressure single-crystal X-ray study

2012 ◽  
Vol 76 (4) ◽  
pp. 963-973 ◽  
Author(s):  
G. O. Lepore ◽  
T. Boffa Ballaran ◽  
F. Nestola ◽  
L. Bindi ◽  
D. Pasqual ◽  
...  
Keyword(s):  
Pressure Range ◽  
Substantial Reduction ◽  
Structural Data ◽  
Unit Cell ◽  
Van Der Waals Interactions ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters ◽  
Intermolecular Distances

AbstractAmbient temperature X-ray diffraction data were collected at different pressures from two crystals of β-As4S4, which were made by heating realgar under vacuum at 295ºC for 24 h. These data were used to calculate the unit-cell parameters at pressures up to 6.86 GPa. Above 2.86 GPa, it was only possible to make an approximate measurement of the unit-cell parameters. As expected for a crystal structure that contains molecular units held together by weak van der Waals interactions, β-As4S4 has an exceptionally high compressibility. The compressibility data were fitted to a third-order Birch–Murnaghan equation of state with a resulting volume V0 = 808.2(2) Å3, bulk modulus K0 = 10.9(2) GPa and K' = 8.9(3). These values are extremely close to those reported for the low-temperature polymorph of As4S4, realgar, which contains the same As4S4 cage-molecule. Structural analysis showed that the unit-cell contraction is due mainly to the reduction in intermolecular distances, which causes a substantial reduction in the unit-cell volume (∼21% at 6.86 GPa). The cage-like As4S4 molecules are only slightly affected. No phase transitions occur in the pressure range investigated.Micro-Raman spectra, collected across the entire pressure range, show that the peaks associated with As–As stretching have the greatest pressure dependence; the S–As–S bending frequency and the As–S stretching have a much weaker dependence or no variation at all as the pressure increases; this is in excellent agreement with the structural data.

Synthesis and crystal structure of (Ag,Pd)22Se6

2013 ◽  
Vol 28 (1) ◽  
pp. 13-17 ◽  
Author(s):  
F. Laufek ◽  
A. Vymazalová ◽  
D.A. Chareev ◽  
A.V. Kristavchuk ◽  
J. Drahokoupil ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Diffraction Data ◽  
Glass Tube ◽  
Structure Type ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
Synthesis And Crystal Structure ◽  
X Ray ◽  
Cell Parameters ◽  
Silica Glass Tube

The (Ag,Pd)22Se6 phase was synthesized from individual elements by silica glass tube technique and structurally characterized from powder X-ray diffraction data. The (Ag,Pd)22Se6 phase crystallizes in Fm$\overline3$m symmetry, unit-cell parameters: a = 12.3169(2) Å, V = 1862.55(5) Å3, Z = 4, and Dc = 10.01 g/cm3. The crystal structure of the (Ag,Pd)22Se6 phase represents a stuffed 3a.3a.3a superstructure of the Pd structure (fcc), where only 4 from 108 available octahedral holes are occupied. Its crystal structure is related to the Cr23C6 structure type.

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