(Ba, Sr)3MgSi2O8 structure change caused by Ba/Sr replacement

2014 ◽  
Vol 30 (1) ◽  
pp. 40-51 ◽  
Author(s):  
Yoshinori Yonezaki
Keyword(s):  
Raman Spectroscopy ◽  
Interlayer Space ◽  
Rietveld Method ◽  
Structure Change ◽  
Solid Solution Series ◽  
Structural Refinement ◽  
X Ray Diffraction ◽  
Size Mismatch ◽  
Structural Symmetry ◽  
X Ray

Crystal structure of BaxSr3–xMgSi2O8 has been determined by Raman spectroscopy and X-ray diffraction. The solid solution series have glaserite-type layered structures made of corner-sharing SiO4 tetrahedra and MgO6 octahedra. Ba2+ and Sr2+ ions are sandwiched in between the layers. Raman spectroscopy has found that structural symmetry changes at x = 0.5 and 2.5. Structural refinement by the Rietveld method has clarified that the symmetry changes occur among C2 (Z = 4), P${\bar 3}$m1 (Z = 1), and P${\bar 3}$ (Z = 3). They originate in SiO4 tilting caused by size mismatch between alkali–earth cations and their site spaces. For x ≤ 0.5, SiO4 tilting occur every other interlayer space, whereas for x ≥ 2.5, all the SiO4 tilt.

scholarly journals Characterization and Luminescence of Eu3+- and Gd3+-Doped Hydroxyapatite Ca10(PO4)6(OH)2

Crystals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 806 ◽  
Author(s):  
Veronica Paterlini ◽  
Marco Bettinelli ◽  
Rosanna Rizzi ◽  
Asmaa El Khouri ◽  
Manuela Rossi ◽  
...  
Keyword(s):  
Rare Earth ◽  
Rietveld Method ◽  
Structure Characterization ◽  
Luminescence Spectroscopy ◽  
Structural Refinement ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cell Parameters ◽  
Strong Luminescence ◽  
Bio Imaging

Luminescence properties of europium-doped Ca10-xEux(PO4)6(OH)2 (xEu = 0, 0.01, 0.02, 0.10 and 0.20) and gadolinium-doped hydroxyapatite Ca9.80Gd0.20(PO4)6(OH)2 (HA), synthesized via solid-state reaction at T = 1300 °C, were investigated using scanning electron microscopy (SEM), powder X-ray diffraction (PXRD), Fourier transform infrared (FTIR), and luminescence spectroscopy. Crystal structure characterization (from unit cell parameters determination to refined atomic positions) was achieved in the P63/m space group. FTIR analyses show only slight band shifts of (PO4) modes as a function of the rare earth concentration. Structural refinement, achieved via the Rietveld method, and luminescence spectroscopy highlighted the presence of dopant at the Ca2 site. Strong luminescence was observed for all Eu- and Gd-doped samples. Our multi-methodological study confirms that rare-earth (RE)-doped synthetic hydroxyapatites are promising materials for bio-imaging applications.

Raman spectroscopy and X‐ray diffraction of pressure‐induced reversible structure change in K 2 OsO 2 (OH) 4

2020 ◽  
Vol 51 (7) ◽  
pp. 1240-1247
Author(s):  
Qiqi Tang ◽  
Shan Liu ◽  
Binbin Wu ◽  
Feng Zhang ◽  
Li Lei
Keyword(s):  
Raman Spectroscopy ◽  
Structure Change ◽  
X Ray Diffraction ◽  
X Ray

Structural Refinement by the Rietveld Method on Clinkers Obtained from Waste from Pulp and Paper Mills

2018 ◽  
Vol 912 ◽  
pp. 175-179 ◽  
Author(s):  
Lisandro Simão ◽  
J. Jiusti ◽  
N.J. Lóh ◽  
D. Hotza ◽  
F. Raupp-Pereira ◽  
...  
Keyword(s):  
Rietveld Method ◽  
Pulp And Paper ◽  
Cement Industry ◽  
Processing Conditions ◽  
Structural Refinement ◽  
X Ray Diffraction ◽  
Pulp And Paper Mills ◽  
Paper Mills ◽  
X Ray ◽  
Biomass Ashes

Pulp and paper mills have a process that generates waste with high levels of CaO and SiO2, which can be valued as an alternative mineral source in the cement industry. In this work the lime mud, biomass ashes and WWTP sludge are used in the production of clinker. Analysis of X-ray diffraction (XRD) confirmed the crystalline phases calcite and quartz. Chemical analysis by X-ray fluorescence (XRF) identified Al2O3, CaO and SiO2, providing support for the calculation of theoretical stages by applying the Bogue equations. Five formulations and three processing temperatures (1350, 1400, 1455 °C) were studied. The products obtained and an ordinary Portland cement (OPC) were characterized by XRD with quantification by the Rietveld method. The results showed that the processing conditions used produced belíticos (higher content of C2S) and Portland (C3S content greater) ecoclinker.

Growth, optical and EPR properties of Li1.72Na0.28Ge4O9 single crystals pure and slightly doped with Cr

Open Physics ◽  
2012 ◽  
Vol 10 (2) ◽  
Author(s):  
Anna Jasik ◽  
Marek Berkowski ◽  
Slawomir Kaczmarek ◽  
Andrzej Suchocki ◽  
Agata Kaminska ◽  
...  
Keyword(s):  
Single Crystals ◽  
Ambient Atmosphere ◽  
Solid Solution Series ◽  
Photoluminescence Spectra ◽  
Czochralski Technique ◽  
Structural Refinement ◽  
X Ray Diffraction ◽  
X Ray ◽  
X Band ◽  
Field Modulation

AbstractSingle crystals of lithium-sodium-tetragermanate, a member of the solid solution series Li2−xNaxGe4O9 with x=0.28, pure and slightly doped with Cr3+ ions (0.03 mol.% and 0.1 mol.%), were grown in ambient atmosphere by the Czochralski technique from stoichiometric melt. The crystals with dimensions up to 20 mm in diameter and 50 mm in length were obtained. The crystal structure has been determined by means of X-ray diffraction. Phase analysis and structural refinement of the Li1.72Na0.28Ge4O9 crystals were performed by X-ray powder diffraction using Ni-filtered Cu Kα radiation with a Siemens D5000 diffractometer. The absorption, excitation and photoluminescence spectra of the crystals were measured in the UV-VIS and IR range at low temperatures. EPR investigations were performed using a conventional X-band Bruker ELEXSYS E 500 CW-spectrometer operating at 9.5 GHz with 100 kHz magnetic field modulation. Temperature and angular dependences of the EPR spectra of the crystal samples were recorded in the 3–300 K temperature range.

scholarly journals Structural modification by adding Li cations into Mg/Cs-TFSA molten salt facilitating Mg electrodeposition

RSC Advances ◽  
2015 ◽  
Vol 5 (4) ◽  
pp. 3063-3069 ◽  
Author(s):  
Koji Ohara ◽  
Yasuhiro Umebayashi ◽  
Tetsu Ichitsubo ◽  
Kazuhiko Matsumoto ◽  
Rika Hagiwara ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Monte Carlo ◽  
Molten Salt ◽  
Molecular Mechanics ◽  
Structural Modification ◽  
High Energy ◽  
Reverse Monte Carlo ◽  
Structural Refinement ◽  
X Ray Diffraction ◽  
X Ray

Free volume around Mg ions in Li/Mg/Cs-TFSA by adding Li cations would facilitate the Mg electrodeposition, which has been studied by Raman spectroscopy, high-energy X-ray diffraction, and reverse Monte Carlo structural refinement using molecular mechanics.

New arsenate minerals from the Arsenatnaya fumarole, Tolbachik volcano, Kamchatka, Russia. XIII. Pansnerite, K3Na3Fe3+6(AsO4)8

2019 ◽  
Vol 84 (1) ◽  
pp. 143-151 ◽  
Author(s):  
Igor V. Pekov ◽  
Natalia V. Zubkova ◽  
Natalia N. Koshlyakova ◽  
Atali A. Agakhanov ◽  
Dmitry I. Belakovskiy ◽  
...  
Keyword(s):  
Interlayer Space ◽  
Scoria Cone ◽  
New Mineral ◽  
Solid Solution Series ◽  
X Ray Diffraction ◽  
X Ray ◽  
Tolbachik Volcano ◽  
Mohs Hardness ◽  
Hexagonal Crystals ◽  
Light Green

AbstractThe new mineral pansnerite, ideally K3Na3Fe3+6(AsO4)8, was found in the Arsenatnaya fumarole at the Second scoria cone of the Northern Breakthrough of the Great Tolbachik Fissure Eruption, Tolbachik volcano, Kamchatka, Russia. It is associated with aphthitalite, hematite, sanidine, badalovite, khrenovite, achyrophanite, arsenatrotitanite, ozerovaite, tilasite, calciojohillerite, johillerite, nickenichite, svabite, katiarsite, yurmarinite, anhydrite, rutile, cassiterite and pseudobrookite. Pansnerite forms tabular to lamellar (flattened on {010}), usually pseudo-hexagonal crystals up to 0.2 mm × 0.7 mm × 1 mm and crystal clusters up to 2 mm across. It is transparent to translucent, light green, pale greenish, yellowish–greenish or yellowish, with vitreous lustre. The mineral is brittle, with perfect {010} cleavage. The Mohs’ hardness is ca 3. Dcalc is 3.596 g cm–3. Pansnerite is optically biaxial (–), α = 1.702(4), β = 1.713(4), γ = 1.717(4), 2Vmeas = 45(10)° and 2Vcalc = 62°. Chemical composition (holotype, wt.%, electron microprobe data) is: Na2O 6.39, K2O 8.52, CaO 0.08, MgO 0.08, MnO 0.02, NiO 0.02, CuO 1.35, ZnO 0.34, Al2O3 7.35, Cr2O3 0.04, Fe2O3 16.72, SiO2 0.16, P2O5 0.22, V2O5 0.09, As2O5 57.76, SO3 0.04, total 99.20. The empirical formula based on 32 O apfu is K2.86Na3.26Ca0.02(Fe3+3.31Al2.28Cu0.27Zn0.07Mg0.03Cr0.01)Σ5.97(As7.95P0.05Si0.04V0.02S0.01)Σ8.06O32. Pansnerite is orthorhombic, Cmce, a = 10.7372(3), b = 20.8367(8), c = 6.47335(15) Å, V = 1448.27(7) Å3 and Z = 2. The strongest reflections of the X-ray powder diffraction pattern [d,Å(I)(hkl)] are: 10.49(100)(020), 5.380(88)(111), 4.793(65)(220), 3.105(46)(311, 002), 3.079(32)(112, 061), 2.932(35)(260), 2.783(65)(202) and 2.694(52)(400, 222). The crystal structure was solved from single-crystal X-ray diffraction data, R1 = 2.82%. The structure is based on heteropolyhedral layers formed by MO6 octahedra (M = Fe3+ and Al) sharing common vertices and connected by AsO4 tetrahedra. Na+ and K+ cations are located in the interlayer space. The mineral is named in honour of the German–Russian mineralogist and geographer Lavrentiy Ivanovich Pansner (1777–1851). Pansnerite forms a solid-solution series with the isotypic mineral ozerovaite, ideally KNa2Al3(AsO4)4.

scholarly journals New Ca2.90(Me2+)0.10(PO4)2 β-tricalcium Phosphates with Me2+ = Mn, Ni, Cu: Synthesis, Crystal-Chemistry, and Luminescence Properties

Crystals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 288 ◽  
Author(s):  
Angela Altomare ◽  
Rosanna Rizzi ◽  
Manuela Rossi ◽  
Asmaa El Khouri ◽  
Mohammed Elaatmani ◽  
...  
Keyword(s):  
Tricalcium Phosphate ◽  
Rietveld Method ◽  
Unit Cell ◽  
Luminescence Properties ◽  
Luminescence Spectroscopy ◽  
Luminescence Spectra ◽  
Structural Refinement ◽  
X Ray Diffraction ◽  
X Ray ◽  
Tricalcium Phosphates

C a 2.90 M e 0.10 2 + ( P O 4 ) 2 (with Me = Mn, Ni, Cu) β-tricalcium phosphate (TCP) powders were synthesized by solid-state reaction at T = 1200 °C and investigated by means of a combination of scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDS), powder X-ray diffraction (PXRD), Fourier transform infrared (FTIR) spectroscopy, and luminescence spectroscopy. SEM morphological analysis showed the run products to consist of sub spherical microcrystalline aggregates, while EDS semi-quantitative analysis confirmed the nominal Ca/Me composition. The unit cell and the space group were determined by X-ray powder diffraction data showing that all the compounds crystallize in the rhombohedral R3c whitlockite-type structure, with the following unit cell constants: a = b = 10.41014(19) Å, c = 37.2984(13) Å, and cell volume V = 3500.53(15) Å3 (Mn); a = b = 10.39447(10) Å, c = 37.2901(8) Å; V = 3489.22(9) Å3 (Ni); a = b = 10.40764(8) Å, c = 37.3158(6) Å, V = 3500.48(7) Å3 (Cu). The investigation was completed with the structural refinement by the Rietveld method. The FTIR spectra are similar to those of the end-member Ca β-tricalcium phosphate (TCP), in agreement with the structure determination, and show minor band shifts of the (PO4) modes with the increasing size of the replacing Me2+ cation. Luminescence spectra and decay curves revealed significant luminescence properties for Mn and Cu phases.

Raman spectroscopy and X-ray diffraction of lithium niobate at temperatures up to 1300○-4.80pt○C

2005 ◽  
Vol 126 ◽  
pp. 101-105 ◽  
Author(s):  
B. Moulin ◽  
L. Hennet ◽  
D. Thiaudière ◽  
P. Melin ◽  
P. Simon
Keyword(s):  
Raman Spectroscopy ◽  
Lithium Niobate ◽  
X Ray Diffraction ◽  
X Ray

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 Structural and Raman Vibrational Studies ofCeO2-Bi2O3Oxide System

2009 ◽  
Vol 2009 ◽  
pp. 1-4 ◽  
Author(s):  
L. Bourja ◽  
B. Bakiz ◽  
A. Benlhachemi ◽  
M. Ezahri ◽  
J. C. Valmalette ◽  
...  
Keyword(s):  
Solid Solution ◽  
Raman Spectroscopy ◽  
Phase Changes ◽  
Phase System ◽  
X Ray Diffraction ◽  
X Ray ◽  
Vibrational Studies ◽  
Coprecipitation Route

A series of ceramics samples belonging to theCeO2-Bi2O3phase system have been prepared via a coprecipitation route. The crystallized phases were obtained by heating the solid precursors at600∘Cfor 6 hours, then quenching the samples. X-ray diffraction analyses show that forx<0.20a solid solutionCe1−xBixO2−x/2with fluorine structure is formed. For x ranging between 0.25 and 0.7, a tetragonalβ′phase coexisting with the FCC solid solution is observed. For x ranging between 0.8 and 0.9, a new tetragonalβphase appears. Theβ′phase is postulated to be a superstructure of theβphase. Finally, close tox=1, the classical monoclinicα Bi2O3structure is observed. Raman spectroscopy confirms the existence of the phase changes as x varies between 0 and 1.

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