Crystal chemistry of aegirine as an indicator of P-T conditions

2007 ◽  
Vol 71 (3) ◽  
pp. 321-326 ◽  
Author(s):  
L. Secco ◽  
A. Guastoni ◽  
F. Nestola ◽  
G. J. Redhammer ◽  
A. Dal Negro
Keyword(s):  
Cell Volume ◽  
Atmospheric Pressure ◽  
Synthesis Temperature ◽  
X Ray Diffraction ◽  
Β Cell ◽  
X Ray ◽  
Cell Parameters ◽  
Different Temperatures ◽  
The Difference ◽  
Polyhedral Volumes

AbstractOne metamorphic and four magmatic aegirines, together with two end-member aegirines synthesized at atmospheric pressure and different temperatures, were investigated by single-crystal X-ray diffraction. The limited compositional differences allow the polyhedral volumes to be almost constant in all the aegirines investigated( VM1 ≈ 11.0 Å3; VM2 ≈ 26.3 Å3; VT ≈ 2.21 Å3). However, differences in polyhedral distortions are responsible for the cell-volume variations, reflected mainly in the change of a and β cell parameters. Cell volume is only partly related to the composition of these aegirines: with increasing formation temperature, an increase in the unit-cell volume of ~1.2 Å3 is observed, while a significant contraction of the cell volume occurs during high-pressure formation. As the difference in cell volume between the two synthetic aegirines is ascribed to the different conditions of synthesis temperature, the same interpretation could be adopted for the differences observed in natural aegirines.

scholarly journals Bulachite, [Al6(AsO4)3(OH)9(H2O)4]⋅2H2O from Cap Garonne, France: Crystal structure and formation from a higher hydrate

2020 ◽  
Vol 84 (4) ◽  
pp. 608-615
Author(s):  
Ian E. Grey ◽  
Emre Yoruk ◽  
Stéphanie Kodjikian ◽  
Holger Klein ◽  
Catherine Bougerol ◽  
...  
Keyword(s):  
Unit Cell ◽  
Orthorhombic Symmetry ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
Space Group ◽  
X Ray ◽  
Cell Parameters ◽  
Different Temperatures ◽  
Using Data ◽  
Hydrated Aluminium

AbstractBulachite specimens from Cap Garonne, France, comprise two intimately mixed hydrated aluminium arsenate minerals with the same Al:As ratio of 2:1 and with different water contents. The crystal structures of both minerals have been solved using data from low-dose electron diffraction tomography combined with synchrotron powder X-ray diffraction. One of the minerals has the same powder X-ray diffraction pattern (PXRD) as for published bulachite. It has orthorhombic symmetry, space group Pnma with unit-cell parameters a = 15.3994(3), b = 17.6598(3), c = 7.8083(1) Å and Z = 4, with the formula [Al6(AsO4)3(OH)9(H2O)4]⋅2H2O. The second mineral is a higher hydrate with composition [Al6(AsO4)3(OH)9(H2O)4]⋅8H2O. It has the same Pnma space group and unit-cell parameters a = 19.855(4), b = 17.6933(11) and c = 7.7799(5) Å i.e. almost the same b and c parameters but a much larger a parameter. The structures are based on polyhedral layers, parallel to (100), of composition [Al6(AsO4)3(OH)9(H2O)4] and with H-bonded H2O between the layers. The layers contain [001] spiral chains of edge-shared octahedra, decorated with corner connected AsO4 tetrahedra that are the same as in the mineral liskeardite. The spiral chains are joined together by octahedral edge-sharing to form layers parallel to (100). Synchrotron PXRD patterns collected at different temperatures during heating of the specimen show that the higher-hydrate mineral starts transforming to bulachite when heated to 50°C, and the transformation is complete between 75 and 100°C.

X-ray powder diffraction data for 2-[((3R)-5-oxo-4-phenyltetrahy drofuran-3-yl)methyl]isoindoline-1,3-dione, C19H15NO4

2016 ◽  
Vol 31 (2) ◽  
pp. 155-158
Author(s):  
Shoujun Zheng ◽  
Kailin Xu ◽  
Qing Wang ◽  
XiaoLin Tang ◽  
Yanmei Huang ◽  
...  
Keyword(s):  
Cell Volume ◽  
Powder Diffraction ◽  
Unit Cell Volume ◽  
Unit Cell ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
Element Analysis ◽  
Space Group ◽  
X Ray ◽  
Cell Parameters

2-[((3R)-5-oxo-4-phenyltetrahydrofuran-3-yl)methyl]isoindoline-1,3-dione, C19H15NO4, was synthesized for the first time. Its structure was characterized by element analysis, ultraviolet spectrometry, nuclear magnetic resonance, and single X-ray diffraction (SXRD). X-ray powder diffraction (XRPD) data of title compound were collected and calculated. The result of SXRD shows that its crystal system is orthorhombic, space group is Pbca, and unit-cell parameters are a = 8.861 57(7), b = 14.6666(10), c = 24.4247(19) Å, α =β =γ =90°, unit-cell volume V = 3174.4 Å3, and Z = 8. All XRPD measured lines were indexed and consistent with the Pbca space group [a = 14.639(7), b = 24.378(3), c = 8.918(1) Å, α = β = γ = 90°, unit-cell volume V = 3182.7(9) Å3, Z = 8]. No detectable impurities were observed.

A new mineral, zincolibethenite, CuZnPO4OH, a stoichiometric species of specific site occupancy

2005 ◽  
Vol 69 (2) ◽  
pp. 145-153 ◽  
Author(s):  
R. S. W. Braithwaite ◽  
R. G. Pritchard ◽  
W. H. Paar ◽  
R. A. D. Pattrick
Keyword(s):  
Atmospheric Pressure ◽  
Site Occupancy ◽  
New Mineral ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
Cation Site ◽  
Calculated Density ◽  
X Ray ◽  
Cell Parameters ◽  
Jahn Teller

AbstractTiny green crystals from Kabwe, Zambia, associated with hopeite and tarbuttite (and probably first recorded in 1908 but never adequately characterized because of their scarcity) have been studied by X-ray diffraction, microchemical and electron probe microanalysis, infrared spectroscopy, and synthesis experiments. They are shown to be orthorhombic, stoichiometric CuZnPO4OH, of species rank, forming the end-member of a solid-solution series to libethenite, Cu2PO4OH, and are named zincolibethenite. The libethenite structure is unwilling to accommodate any more Zn substituting for Cu at atmospheric pressure, syntheses using Zn-rich solutions precipitating a mixture of zincolibethenite with hopeite, Zn3(PO4)2.4H2O. Single-crystal X-ray data confirm that the Cu(II) occupies the Jahn-Teller distorted 6-coordinate cation site in the libethenite lattice, and the Zn(II) occupies the 5-coordinate site. The space group of zincolibethenite is Pnnm, the same as that of libethenite, with unit-cell parameters a = 8.326, b = 8.260, c = 5.877 Å , V = 404.5 Å 3, Z = 4, calculated density = 3.972 g/cm3 (libethenite has a = 8.076, b = 8.407, c = 5.898 Å , V = 400.44 Å 3, Z = 4, calculated density = 3.965 g/cm3). Zincolibethenite is biaxial negative, with 2Vα(calc.) of 49°, r<v, and α = 1.660, β = 1.705, and γ = 1.715 The mineral is named for its relationship to libethenite.

X-ray diffraction data of 4-phenyl-6-(trifluoromethyl)-3,4-dihydroquinolin-2(1H)-one and its synthetic precursor N-[4-(trifluoromethyl)phenyl]cinnamamide

2016 ◽  
Vol 31 (3) ◽  
pp. 233-239
Author(s):  
Jose H. Quintana Mendoza ◽  
J. A. Henao ◽  
Carlos E. Rondón Flórez ◽  
Carlos E. Puerto Galvis ◽  
Vladimir V. Kouznetsov
Keyword(s):  
Cell Volume ◽  
Title Compound ◽  
Unit Cell Volume ◽  
Unit Cell ◽  
Chemical Formula ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
Monoclinic System ◽  
X Ray ◽  
Cell Parameters

The title compound, the 4-phenyl-6-(trifluoromethyl)-3,4-dihydroquinolin-2(1H)-one (4) with chemical formula: (C16H12F3NO), was synthesized from N-[4-(trifluoromethyl)phenyl]cinnamamide (3), chemical formula: (C16H12F3NO), through an intramolecular cyclization mediated by triflic acid. Preliminary molecular characterization of both compounds was performed by Fourier transform infrared spectroscopy, gas chromatography mass spectrometry, and nuclear magnetic resonance spectroscopy (1H, 13C); crystallographic characterization was completed by X-ray diffraction of polycrystalline samples. The title compound 4 crystallized in a monoclinic system and unit-cell parameters are reported [a = 16.002 (3), b = 5.170 (1), c = 17.733 (3) Å, β = 111.11 (2)°, unit-cell volume V = 1368.5 (3) Å3, Z = 4] P21/c (No. 14) space group; the title compound 3 crystallized in a monoclinic system and unit-cell parameters are reported [a = 12.902 (2), b = 5.144 (1), c = 20.513 (5) Å, β = 91.67 (2)°, unit-cell volume V = 1360.7 (4) Å3, Z = 4] P21/c (No. 14) space group.

scholarly journals Crystal Chemistry and Structural Variations for Zircon Samples from Various Localities

Minerals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 947 ◽  
Author(s):  
M. Zaman ◽  
Sytle Antao
Keyword(s):  
Cell Volume ◽  
Unit Cell Volume ◽  
Structural Parameters ◽  
Unit Cell ◽  
Radiation Doses ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters ◽  
Zircon Sample

This study investigates the variations of structural parameters and chemistry of a partially metamict and seven detrital zircon samples from different localities using single-crystal X-ray diffraction, synchrotron high-resolution powder X-ray diffraction, and electron-probe micro-analysis techniques. The unit-cell parameters for the eight zircon samples vary linearly with increasing unit-cell volume, V. A zircon sample from the Canadian Arctic Islands has the smallest unit-cell parameters, bond distances, ideal stoichiometric composition, unaffected by α-radiation damage, and is chemically pure. A zircon sample from Jemaa, Nigeria has the largest unit-cell parameters because of the effect of α-radiation doses received over a long time (2384 Ma). All the samples show good correlations between Zr and Si apfu (atom per formula unit) versus unit-cell volume, V. The α-radiation doses in the samples are lower than ~3.5 × 1015 α-decay events/mg. Substitutions of other cations at the Zr and Si sites control the variations of the structural parameters. Relatively large unit-cell parameters and bond distances occur because the Zr site accommodates other cations that have larger ionic radii than the Zr atom. Geological age increases the radiation doses in zircon and it is related to V.

Gemmological investigation of a synthetic blue beryl: a multi-methodological study

2008 ◽  
Vol 72 (3) ◽  
pp. 799-808 ◽  
Author(s):  
I. Adamo ◽  
G. D. Gatta ◽  
N. Rotiroti ◽  
V. Diella ◽  
A. Pavese
Keyword(s):  
Crystal Structure ◽  
Inductively Coupled Plasma ◽  
Tetrahedral Site ◽  
X Ray Diffraction ◽  
Thermo Gravimetric ◽  
X Ray ◽  
Cell Parameters ◽  
Inductively Coupled ◽  
The Difference ◽  
Difference Fourier

AbstractA multi-methodological investigation of a synthetic Cu/Fe-bearing blue beryl [IV(Be2.86Cu0.14)∑=3.00VI(Al1.83Fe3+0.14Mn2+0.03Mg0.03)∑=2.03IV(Si5.97Al0.03∑=6.00O18.(Li0.12Na0.04.0.40H2O)] has been performed by means of gemmological standard testing, electron microprobe chemical analyses, laser ablation inductively coupled plasma mass spectroscopy, thermo-gravimetric analyses, infrared spectroscopy and single-crystal X-ray diffraction in order to determine the gemmological properties, crystal structure and crystal-chemistry of this material. The increasing production of marketable hydrothermal synthetic beryls with 'exotic' colours and the small number of studies on the accurate location of chromophores in the crystal structure inspired this multi-methodological investigation. The X-ray structural refinements confirm that the space group of the Cu/Fe-bearing blue beryl is P6/mcc, with unit-cell parameters: 9.2483 ≤ a ≤ 9.2502 Å and 9.2184 ≤ c ≤ 9.2211 Å. The analysis of the difference Fourier maps of the electron density suggests that Cu is located at the tetrahedral site (Wyckoff 6fposition) along with Be, whereas Fe shares the octahedral site with Al (4c position). No evidence of extra-framework Cu/Fe-sites (i.e. channel sites) has been found. The Li is probably located at the extra-framework 2b site. Infrared spectra show that the H2O molecules are present with two configurations: one with the H···H vector oriented ‖[0001] and the other with H···H vector oriented ⊥[0001].

TEMPERATURE EFFECT ON STRUCTURAL AND ELECTRONIC PROPERTIES OF ZINC OXIDE NANOWIRES SYNTHESIZED BY CARBOTHERMAL EVAPORATION METHOD

2012 ◽  
Vol 11 (05) ◽  
pp. 1250032 ◽  
Author(s):  
MOHAMMAD ORVATINIA ◽  
ROGHAYEH IMANI
Keyword(s):  
Zinc Oxide ◽  
Grain Boundary ◽  
Elevated Temperatures ◽  
Synthesis Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Si Substrates ◽  
Structural And Electronic Properties ◽  
Different Temperatures ◽  
Sem Micrograph

Zinc Oxide ( ZnO ) nanowires were synthesized on the Si substrates by carbothermal evaporation of ZnO + C at elevated temperatures. The syntheses were carried out at different temperatures from 750°C to 950°C. Characterizations of layers were performed to study the effect of synthesis temperature on morphology, crystal structure and electrical behavior of fabricated nanowires. The physical characterization was performed by scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy dispersive X-ray (EDAX) methods. SEM micrograph of layers revealed that the samples grown at the lower temperatures have better quality. However, below 800°C the growth of nanowires was stopped. So the 800°C was concluded to be the optimum temperature for growth of high quality nanowires by proposed system. By recording the conductivity variations as a function of inverse temperature, 1/T, the semiconductor property of the samples was verified. It is demonstrated that two distinct factors affect the electrical conductivity of layers, which are due to the bulk and grain boundary. We experimentally proved that the activation energy corresponding to grain boundary is higher than that of the bulk. As another result we have established for the first time that by increasing synthesis temperatures, both activation energies shift to higher values.

Crystal structure of adamite at high temperature

2016 ◽  
Vol 80 (5) ◽  
pp. 901-914 ◽  
Author(s):  
M. Zema ◽  
S. C. Tarantino ◽  
M. Boiocchi ◽  
A. M. Callegari
Keyword(s):  
Crystal Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Maximum Expansion ◽  
Cell Parameters ◽  
Temperature Range ◽  
Linear Evolution ◽  
Thermal Expansion Coefficients ◽  
Different Temperatures ◽  
Increasing Temperature

AbstractStructural modifications with temperature of adamite, Zn2(AsO4)(OH), were determined by single-crystal X-ray diffraction up to dehydration and collapse of the crystal structure. In the temperature range 25–400°C, adamite shows positive and linear expansion. Axial thermal expansion coefficients, determined over this temperature range, are αa = 1.06(2) × 10–5 K–1, αb = 1.99(2) × 10–5 K–1, αc = 3.7(1) × 10–6 K–1 and αV = 3.43(3) × 10–5 K–1. Axial expansion is then strongly anisotropic with αa:αb:αc = 2.86: 5.38 : 1. Structure refinements of X-ray diffraction data collected at different temperatures allowed us to characterize the mechanisms by which the adamite structure accommodates variations in temperature. Expansion is limited mainly by edge sharing Zn(2) dimers along a and by edge sharing Zn(1) octahedra chains along c; on the other hand, connections of polyhedra along b, the direction of maximum expansion, is governed by corner sharing. Increasing temperature induces mainly an axial expansion of Zn(1) octahedron, which becomes more elongated, and no significant variations of the Zn(2) trigonal bipyramids and As tetrahedra. Starting from 400°C, deviation from a linear evolution of unit-cell parameters is observed, associated with some deterioration of the crystal, a sign of incipient dehydration. The process leads to the formation of Zn4(AsO4)2O.

scholarly journals Low Temperature Synthesis of Aegirine NaFeSi2O6: Spectroscopy (57Fe Mössbauer, Raman) and Size/Strain Analysis from X-ray Powder Diffraction

Minerals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 444 ◽  
Author(s):  
Günther J. Redhammer ◽  
Julian Weber ◽  
Gerold Tippelt ◽  
Gregor A. Zickler ◽  
Andreas Reyer
Keyword(s):  
Low Temperature ◽  
Crystallite Size ◽  
Synthesis Temperature ◽  
X Ray Diffraction ◽  
Low Temperature Synthesis ◽  
Temperature Synthesis ◽  
X Ray ◽  
Cell Parameters ◽  
57Fe Mössbauer ◽  
Phase Pure

Using a low temperature synthesis protocol, it was possible to obtain phase-pure synthetic aegirine (NaFeSi2O6) at temperatures as low as 130 °C, albeit only with rather long synthesis times of ~200 h; at 155 °C, a nano-crystallite shaped phase-pure material is formed after 24 h. These are, to the best of our knowledge, the lowest temperatures reported so far for phase-pure aegirine synthesis. Powder X-ray diffraction (PXRD) was used to characterize phase purity, structural state and microstructural properties (size and strain) of the as-synthesized (130–230 °C) and heat treated (300–900 °C) samples, via Rietveld analysis of powder patterns. Melting was observed at 999 °C. With increasing synthesis temperature, crystallite size linearly increased from 10 nm to 30 nm at 230 °C, while unit cell parameters decreased. The microstrain was very small. Additional heat treatment of as synthesized samples showed that the crystallite size remained rather unaffected up to 700 °C. The lattice parameters, however, already changed at low temperatures and successively became smaller, indicating increasing ordering towards more regular arrangements of building units. This was confirmed by 57Fe Mössbauer spectroscopy, where a distinct decrease of the quadrupole splitting with increasing synthesis temperature was found. Finally, Raman spectroscopy showed that some weakly-developed pre-ordering effects were present in the samples, which appeared to be amorphous in PXRD, while well-resolved spectra appeared as soon as the long-range ordered crystalline state could be found with X-ray diffraction.

X-Ray Diffraction, and Raman Scattering Study of Nanostructured ZrO2-TiO2 Oxides Prepared by Sol–Gel

2008 ◽  
Vol 8 (12) ◽  
pp. 6623-6629 ◽  
Author(s):  
M. E. Manriquez ◽  
M. Picquart ◽  
X. Bokhimi ◽  
T. López ◽  
P. Quintana ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Anatase Phase ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters ◽  
Different Temperatures ◽  
Scattering Study ◽  
A Minor

In the present work, we study the phase composition of ZrO2-TiO2 system by means of XRD and Raman spectroscopy, using also TG-ATD, and N2 adsorption isotherms as complementary characterization techniques. TiO2-ZrO2 samples of selected compositions (0, 10, 90, 50 and 100% in weight of TiO2) were prepared by sol–gel method and annealed at three different temperatures (400, 600 and 800 °C). Structural characterization reveals that only the pure oxides are crystalline at 400 °C: TiO2 as anatasa with a minor brookite component, and ZrO2 as a mixture of tetragonal (majority) and monoclinic phases. Following the 600 °C calcination, the TiO2-ZrO2 50–50% sample forms the ZrTiO4 mixed oxide, although this materials remains partly amorphous. In contrast, samples with higher and lower TiO2 content form solid solutions with, respectively, anatasa and tetragonal ZrO2 structures. Zirconium incorporation into the TiO2 lattice leads to the expansion of the unit cell parameters, and it stabilizes the anatase phase, hindering its transformation into rutile. Similarly, dissolving titanium atoms into the ZrO2 structure delays the transformation from the tetragonal to the monoclinic polymorph.

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