Carbon incorporation in plumbogummite-group minerals

2011 ◽  
Vol 75 (1) ◽  
pp. 145-158 ◽  
Author(s):  
I. E. Grey ◽  
F. L. Shanks ◽  
N. C. Wilson ◽  
W. G. Mumme ◽  
W. D. Birch
Keyword(s):  
Organic Carbon ◽  
Rietveld Analysis ◽  
Chemical Analyses ◽  
X Ray Diffraction ◽  
Carbon Incorporation ◽  
X Ray ◽  
Wet Chemical ◽  
Difference Fourier ◽  
Large Contraction ◽  
Direct Confirmation

AbstractNon-stoichiometric, carbon-containing crandallite from Guatemala and plumbogummite from Cumbria have been characterized using electron microprobe (EMPA) and wet-chemical analyses, Rietveld analysis of powder X-ray diffraction (PXRD) patterns, and infrared (IR), Raman and cathodoluminescence (CL) spectroscopies. The samples contain 11.0 and 4.8 wt.% CO2, respectively. The IR spectra for both samples show a doublet in the range 1410–1470 cm–1, corresponding to CO3 vibrations. Direct confirmation of CO3 replacing PO4 was obtained from difference Fourier maps in the Rietveld analysis. Carbonate accounts for 67% of the C in the plumbogummite and 20% of the C in the Guatemalan crandallite, the remainder being present as nano-scale organic carbon. The CO3 substitution for PO4 is manifested in a large contraction of the tetrahedral volume (14–19%) and by a contraction of the a axis, analogous to observations for carbonate-containing fluorapatites. Stoichiometric crandallite from Utah was characterized using the same methods, for comparison with the non-stoichiometric, carbon-bearing phases.

Chemical Synthesis and Properties of Layered Co1-yNiyO2-δOxides (0≤y≤1)

2000 ◽  
Vol 658 ◽  
Author(s):  
A. Manthiram ◽  
R. V. Chebiam ◽  
F. Prado
Keyword(s):  
Layer Structure ◽  
Magnetic Data ◽  
Chemical Analyses ◽  
X Ray Diffraction ◽  
Absorption Bands ◽  
X Ray ◽  
Ni Content ◽  
Wet Chemical ◽  
Oxide Ions ◽  
Structure Layer

ABSTRACTLayered Co1-yNiyO2-δ oxides with 0≤y≤1 have been synthesized by chemically extracting lithium from LiNi1-yCoyO2 with NO2PF6 at ambient temperature. The samples have been characterized by X-ray diffraction, wet-chemical analyses, infrared spectroscopy, and magnetic susceptibility measurements. While NiO2-δ retains the initial O3 (CdCl2 structure) layer structure of LiNiO2, CoO2-δ consists of a mixture of P3 and O1 (CdI2 structure) phases that are formed by a sliding of the oxide ions in the initial O3 structure. CoO2-δ and NiO2-δ have oxygen contents of, respectively, 1.67 and 1.95 and the oxygen content increases with increasing Ni content, y, in Co1-yNiyO2-δ. While CoO2-δ exhibits metallic conductivity as revealed by theabsence of absorption bands in the infrared spectrum, NiO2-δ exhibits semiconducting behavior due to a completely filled t2g band. Magnetic data reveal a transition from antiferromagnetic to ferromagnetic correlations as the Ni content in Co1-yNiyO2-δ increases.

scholarly journals Spectroscopic and Crystal-Chemical Features of Sodalite-Group Minerals from Gem Lazurite Deposits

Minerals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1042
Author(s):  
Nikita V. Chukanov ◽  
Anatoly N. Sapozhnikov ◽  
Roman Yu. Shendrik ◽  
Marina F. Vigasina ◽  
Ralf Steudel
Keyword(s):  
Chemical Analyses ◽  
X Ray Diffraction ◽  
Visible Spectroscopy ◽  
X Ray ◽  
Spin Resonance ◽  
Incommensurate Modulation ◽  
Wet Chemical ◽  
Uv Visible ◽  
Diffraction Patterns ◽  
Subordinate Role

Five samples of differently colored sodalite-group minerals from gem lazurite deposits were studied by means of electron microprobe and wet chemical analyses, infrared, Raman, electron spin resonance (ESR) and UV-Visible spectroscopy, and X-ray diffraction. Various extra-framework components (SO42−, S2− and Cl− anions, S3•−, S2•− and SO3•− radical anions, H2O, CO2, COS, cis- as well as trans- or gauche-S4 neutral molecules have been identified. It is shown that S3•− and S4 are the main blue and purple chromophores, respectively, whereas the S2•− yellow chromophore and SO3•− blue chromophore play a subordinate role. X-ray diffraction patterns of all samples of sodalite-group minerals from lazurite deposits studied in this work contain superstructure reflections which indicate different kinds of incommensurate modulation of the structures.

scholarly journals Study of Structural, Magnetic, and Mossbauer Properties of Dy2Fe16Ga1−xNbx (0.0 ≤ x ≤ 1.0) Prepared via Arc Melting Process

2021 ◽  
Vol 7 (3) ◽  
pp. 42
Author(s):  
Jiba N. Dahal ◽  
Kalangala Sikkanther Syed Ali ◽  
Sanjay R. Mishra
Keyword(s):  
Isomer Shift ◽  
Cell Volume ◽  
Intermetallic Compounds ◽  
Unit Cell Volume ◽  
Rietveld Analysis ◽  
Unit Cell ◽  
X Ray Diffraction ◽  
X Ray ◽  
Arc Melting ◽  
Nb Content

Intermetallic compounds of Dy2Fe16Ga1−xNbx (x = 0.0 to 1.00) were synthesized by arc melting. Samples were investigated for structural, magnetic, and hyperfine properties using X-ray diffraction, vibration sample magnetometer, and Mossbauer spectrometer, respectively. The Rietveld analysis of room temperature X-ray diffraction data shows that all the samples were crystallized in Th2Fe17 structure. The unit cell volume of alloys increased linearly with an increase in Nb content. The maximum Curie temperature Tc ~523 K for x = 0.6 sample is higher than Tc = 153 K of Dy2Fe17. The saturation magnetization decreased linearly with increasing Nb content from 61.57 emu/g for x = 0.0 to 42.46 emu/g for x = 1.0. The Mössbauer spectra and Rietveld analysis showed a small amount of DyFe3 and NbFe2 secondary phases at x = 1.0. The hyperfine field of Dy2Fe16Ga1−xNbx decreased while the isomer shift values increased with the Nb content. The observed increase in isomer shift may have resulted from the decrease in s electron density due to the unit cell volume expansion. The substantial increase in Tc of thus prepared intermetallic compounds is expected to have implications in magnets used for high-temperature applications.

scholarly journals Characterization of ferrite nanoparticles for preparation of biocomposites

2017 ◽  
Vol 8 ◽  
pp. 1257-1265 ◽  
Author(s):  
Urszula Klekotka ◽  
Magdalena Rogowska ◽  
Dariusz Satuła ◽  
Beata Kalska-Szostko
Keyword(s):  
Chemical Method ◽  
Ferrite Nanoparticles ◽  
Chemical Activity ◽  
Nominal Composition ◽  
X Ray Diffraction ◽  
Wet Chemical Method ◽  
X Ray ◽  
Transmission Electron ◽  
Wet Chemical

Ferrite nanoparticles with nominal composition Me0.5Fe2.5O4 (Me = Co, Fe, Ni or Mn) have been successfully prepared by the wet chemical method. The obtained particles have a mean diameter of 11–16 ± 2 nm and were modified to improve their magnetic properties and chemical activity. The surface of the pristine nanoparticles was functionalized afterwards with –COOH and –NH2 groups to obtain a bioactive layer. To achieve our goal, two different modification approaches were realized. In the first one, glutaraldehyde was attached to the nanoparticles as a linker. In the second one, direct bonding of such nanoparticles with a bioparticle was studied. In subsequent steps, the nanoparticles were immobilized with enzymes such as albumin, glucose oxidase, lipase and trypsin as a test bioparticles. The characterization of the nanoparticles was acheived by transmission electron microscopy, X-ray diffraction, energy dispersive X-ray and Mössbauer spectroscopy. The effect of the obtained biocomposites was monitored by Fourier transform infrared spectroscopy. The obtained results show that in some cases the use of glutaraldehyde was crucial (albumin).

Study on Synthesis of Calcium Phosphate Biomaterials Containing SMB

2007 ◽  
Vol 330-332 ◽  
pp. 1033-1036 ◽  
Author(s):  
M.H. Li ◽  
Shu Xin Qu ◽  
R. Shen ◽  
N. Yao ◽  
P.D. Ren ◽  
...  
Keyword(s):  
Calcium Phosphate ◽  
Salvia Miltiorrhiza ◽  
Reaction System ◽  
Absorption Peak ◽  
X Ray Diffraction ◽  
Wet Chemical Method ◽  
Obvious Effect ◽  
X Ray ◽  
Wet Chemical ◽  
Wet Synthesis

Calcium phosphate (CaP) biomaterials containing Chinese medicine, Danshen (Salvia Miltiorrhiza Bunge, SMB), have been synthesized in our previous study via the wet chemical method. However, CaP biomaterials were generally synthesized in the alkaline solution. The purpose of the present study was to investigate the effect of pH on SMB and the influence of SMB on the synthesis of CaP biomaterials. The SMB solutions of different pH from 5.0 to 10.0, were scanned with the UV-VIS spectrophotometer (UV-VIS) in the wavelength ranged from 200.00 to 400.00 nm. CaP biomaterials containing SMB were synthesized from (NH4)2HPO4, Ca(NO3)2, NH4OH and SMB. The filtrates of the wet synthesis of CaP biomaterials containing SMB were measured by UV-VIS. The synthesized CaP biomaterials containing SMB were characterized by the X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR). The results showed that the maximum absorption peak appeared at 281.00 nm for solutions of pH 5.0, 6.0 and 7.0. Although there were a new absorption peaks as the pH were 8.0 and 9.0, the absorption curves of SMB became similar to that of SMB as pH at 7.0 after the pH were readjusted to 7.0. The absorption peak appeared an Einstein shift to 347.00 nm at pH 10.0, which did not return to 281.00 nm when the pH of SMB solution was readjusted to 7.0. The absorption peak of filtrates containing SMB of CaP biomaterials reaction system was still at 281.00 nm when their pH was 7.0 and 8.0. Moreover, SMB had no obvious effect on the phase component and functional groups of products. Hence, it could be predicted that calcium phosphate biomaterials containing SMB, such as DCPD and TCP containing SMB, which could be prepared at the pH ranged from 5.0 to 9.0.

The crystal structure of gatehouseite

2011 ◽  
Vol 75 (6) ◽  
pp. 2823-2832
Author(s):  
P. Elliott ◽  
A. Pring
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Three Dimensional ◽  
Direct Methods ◽  
Chemical Analyses ◽  
X Ray Diffraction ◽  
X Ray ◽  
Manganese Phosphate ◽  
Phosphate Mineral ◽  
Unit Formula

AbstractThe crystal structure of the manganese phosphate mineral gatehouseite, ideally Mn52+(PO4)2(OH)4, space group P212121, a = 17.9733(18), b = 5.6916(11), c = 9.130(4) Å, V= 933.9(4) Å3, Z = 4, has been solved by direct methods and refined from single-crystal X-ray diffraction data (T = 293 K) to an R index of 3.76%. Gatehouseite is isostructural with arsenoclasite and with synthetic Mn52+(PO4)2(OH)4. The structure contains five octahedrally coordinated Mn sites, occupied by Mn plus very minor Mg with observed <Mn—O> distances from 2.163 to 2.239 Å. Two tetrahedrally coordinated P sites, occupied by P, Si and As, have <P—O> distances of 1.559 and 1.558 Å. The structure comprises two types of building unit. A strip of edge-sharing Mn(O,OH)6 octahedra, alternately one and two octahedra wide, extends along [010]. Chains of edge- and corner-shared Mn(O,OH)6 octahedra coupled by PO4 tetrahedra extend along [010]. By sharing octahedron and tetrahedron corners, these two units form a dense three-dimensional framework, which is further strengthened by weak hydrogen bonding. Chemical analyses by electron microprobe gave a unit formula of (Mn4.99Mg0.02)Σ5.01(P1.76Si0.07(As0.07)Σ2.03O8(OH)3.97.

scholarly journals Equimolar Yttria-Stabilized Zirconia and Samaria-Doped Ceria Solid Solutions

Ceramics ◽  
2018 ◽  
Vol 1 (2) ◽  
pp. 343-352 ◽  
Author(s):  
Reginaldo Muccillo ◽  
Daniel de Florio ◽  
Eliana Muccillo
Keyword(s):  
Tetragonal Phase ◽  
Room Temperature ◽  
Single Phase ◽  
Rietveld Analysis ◽  
X Ray Diffraction ◽  
Ceramic Powders ◽  
Stabilized Zirconia ◽  
X Ray ◽  
Ceria Solid Solutions ◽  
Attrition Milling

Compositions of (ZrO2)0.92(Y2O3)0.08 (zirconia: 8 mol % yttria—8YSZ) and (CeO2)0.8(Sm2O3)0.2 (ceria: 20 mol % samaria—SDC20) ceramic powders were prepared by attrition milling to form an equimolar powder mixture, followed by uniaxial and isostatic pressing. The pellets were quenched to room temperature from 1200 °C, 1300 °C, 1400 °C and 1500 °C to freeze the defects configuration attained at those temperatures. X-ray diffraction analyses, performed in all quenched pellets, show the evolution of the two (8YSZ and SDC20) cubic fluorite structural phases to a single phase at 1500 °C, identified by Rietveld analysis as a tetragonal phase. Impedance spectroscopy analyses were carried out in pellets either quenched or slowly cooled from 1500 °C. Heating the quenched pellets to 1000 °C decreases the electrical resistivity while it increases in the slowly cooled pellets; the decrease is ascribed to annealing of defects created by lattice micro-tensions during quenching while the increase to partial destabilization of the tetragonal phase.

scholarly journals Thermal Stability and Kinetics of Formation of Magnesium Oxychloride Phase 3Mg(OH)2∙MgCl2∙8H2O

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 767 ◽  
Author(s):  
Michal Lojka ◽  
Ondřej Jankovský ◽  
Adéla Jiříčková ◽  
Anna-Marie Lauermannová ◽  
Filip Antončík ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Construction Materials ◽  
Simultaneous Thermal Analysis ◽  
Rietveld Analysis ◽  
X Ray Diffraction ◽  
Sustainable Building ◽  
X Ray ◽  
Kinetics Of Formation ◽  
Magnesium Oxychloride ◽  
Kinetics Of

In this paper, magnesium oxychloride cement with stoichiometry 3Mg(OH)2∙MgCl2∙8H2O (MOC 3-1-8) was prepared and characterized. The phase composition and kinetics of formation were studied by X-ray diffraction (XRD) and Rietveld analysis of obtained diffractograms. The chemical composition was analyzed using X-ray fluorescence (XRF) and energy dispersive spectroscopy (EDS). Furthermore, scanning electron microscopy (SEM) was used to study morphology, and Fourier Transform Infrared (FT-IR) spectroscopy was also used for the analysis of the prepared sample. In addition, thermal stability was tested using simultaneous thermal analysis (STA) combined with mass spectroscopy (MS). The obtained data gave evidence of the fast formation of MOC 3-1-8, which started to precipitate rapidly. As the length of the time of ripening increased, the amount of MgO decreased, while the amount of MOC 3-1-8 increased. The fast formation of the MOC 3-1-8 phase at an ambient temperature is important for its application in the production of low-energy construction materials, which corresponds with the challenges of a sustainable building industry.

scholarly journals Alkali Fusion-Leaching Method For Comprehensive Processing Of Fly Ash

2017 ◽  
Vol 2 (2) ◽  
pp. 89 ◽  
Author(s):  
A.A. Shoppert ◽  
I.V. Loginova ◽  
L.I. Chaikin ◽  
D.A. Rogozhnikov
Keyword(s):  
Fly Ash ◽  
Power Plant ◽  
X Ray Diffraction ◽  
Water Leaching ◽  
X Ray ◽  
Comprehensive Utilization ◽  
Alkali Fusion ◽  
Wet Chemical ◽  
Promising Source ◽  
Comprehensive Processing

<p>Fly ash, composed of mullite, hematite, amorphous silica and quartz, is a promising source for the recovery of alumina and silica. Desilication with help of NaOH and alkali fusion-leaching method and utilization of alumina and silica in the fly ash for preparation of sodalite and silica white were explored in this research. The samples were characterized by using wet chemical analysis and X-ray diffraction. The optimal extraction of SiO<sub>2</sub> from Reftinskaya power plant fly ash was 46.2% with leaching at 95 <sup>o</sup>C for 3 h. Sodalite was synthesized at 200 °C for 1 h followed water leaching at 95 °C for 1 h. Silica white with specific surface area 180-220 m2/g was prepared by carbonation of the Na<sub>2</sub>SiO<sub>3</sub> solution at 40 <sup>o</sup>C for 90-120 min. The as-prepared silica has a purity of 98,8%.</p><p>The proposed method is suitable for the comprehensive utilization of the fly ash.</p>

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