Jervisite, NaScSi2O6: Optical Data, Morphology, Raman Spectroscopy, and Crystal Chemistry

2019 ◽  
Vol 57 (4) ◽  
pp. 489-498
Author(s):  
Pietro Vignola ◽  
Nicola Rotiroti ◽  
Frédéric Hatert ◽  
Danilo Bersani ◽  
Sergio Andò ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Raman Spectroscopy ◽  
Refractive Index ◽  
Optical Data ◽  
Synthetic Analogue ◽  
Natural Sample ◽  
X Ray ◽  
Cell Dimensions ◽  
Using Data ◽  
Unit Cell Dimensions

Abstract The crystal structure of jervisite, ideally NaScSi2O6, was refined using single-crystal X-ray data collected using a crystal from the Seula quarry (Baveno, Verbano-Cusio-Ossola province, Italy). The refinement was carried out in the C2/c space group giving the following unit-cell dimensions: a = 9.8478(2) Å, b = 9.0575(1) Å, c = 5.3409(3) Å, β = 106.87(2)°, and V = 455.89(2) Å3 for Z = 4. The previous crystal structure, refined using data from a synthetic analogue and a natural sample, was confirmed and conforms with that of aegirine. The bond-valence calculation and the refined occupancy of the M1 and M2 sites confirm the cation distribution adopted in the empirical formula. Raman spectroscopy and refractive index measurements were also performed, and the morphology was studied in order to provide a complete description of this Sc-bearing Na pyroxene.

Crystal structure of a synthetic aluminoan tantalian titanite: a reconnaissance study

2006 ◽  
Vol 70 (1) ◽  
pp. 115-121 ◽  
Author(s):  
R. P. Liferovich ◽  
R. H. Mitchell
Keyword(s):  
Crystal Structure ◽  
Structural Data ◽  
Rietveld Analysis ◽  
Synthetic Analogue ◽  
X Ray Diffraction ◽  
Coordination Polyhedra ◽  
X Ray ◽  
Ceramic Synthesis ◽  
Cell Dimensions ◽  
Unit Cell Dimensions

AbstractA synthetic analogue, Ca(Ti0.6Al0.2Ta0.16Nb0.04)OSiO4, of an aluminoan tantalian titanite previously described from Craveggia pegmatite (Piemonte, Italy) has been prepared by a ceramic synthesis technique and its crystal structure determined by Rietveld analysis of the powder X-ray diffraction pattern. The synthetic Al-Ta-Nb-rich titanite adopts space group A2/a implying that substitutions at the single octahedral site destroy the coherence of the off-centering of octahedral chains in the titanite structure resulting in a P21/a → A2/a phase transition. Unit-cell dimensions obtained for the Al-Ta-Nb-rich titanite are: a = 7.0649(1) Å; b = 8.7187(1) Å; c = 6.5701(1) Å; β = 113.755(1)°, V = 370.41(1) Å3. The extensive replacement of Ti by Al, Ta and Nb results in a considerable decrease in the distortion of all coordination polyhedra in the structure of this titanite. These structural data suggest that a solid solution CaTi1-x(Alx/2 [Ta,Nb]x/2)OSiO4 (0 ≤ x ≤ 0.4) adopting the titanite structure might exist.

X-Ray and Optical Data for a Rare Earth–Poor Eudialyte from the North–Central Alaska Range

1990 ◽  
Vol 5 (2) ◽  
pp. 89-92 ◽  
Author(s):  
Neil E. Johnson ◽  
Mickey E. Gunter ◽  
Diana N. Solie ◽  
Charles R. Knowles
Keyword(s):  
Rare Earth ◽  
Powder Diffraction ◽  
Weight Percent ◽  
Optical Data ◽  
Alaska Range ◽  
North Central ◽  
X Ray ◽  
The North ◽  
Cell Dimensions ◽  
Unit Cell Dimensions

AbstractPowder X-ray and optical data have been recorded for a sample of exceptionally rare earth-poor eudialyte (Na12(Ca, REE)6(Fe2+,Mn,Mg)3Zr3(Zr,Nb)x[Si9O27−y(OH)y]2[Si3O9]2(C1,F)z, with x = 0. 1–0.9, y = 1–3 and z = 0.7–1.4) from a pegmatitic vein associated with the peralkaline Windy Fork granite in the north–central Alaska range. The eudialyte is uniaxial positive with ω= 1.6062(2), ε= 1.6138 (3) and microprobe analyses indicate that the sum of REE + Yis less than 0.1 weight percent. Refined unit cell dimensions are: a = 14.2572(4), c = 30.1338(27), Dx= 2.67, F30= 128 (0.006, 42), M20= 76. An indexed powder diffraction pattern is given.

scholarly journals X-ray Crystallographic Study of Ranaconitine

2011 ◽  
Vol 6 (11) ◽  
pp. 1934578X1100601
Author(s):  
Yang Li ◽  
Jun-Hui Zhou ◽  
Gui-Jun Han ◽  
Min-Juan Wang ◽  
Wen-Ji Sun ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Diffraction Analysis ◽  
Critical Role ◽  
X Ray Diffraction ◽  
Monoclinic System ◽  
X Ray ◽  
Crystallographic Study ◽  
Cell Dimensions ◽  
Unit Cell Dimensions

The crystal structure of natural diterpenoid alkaloid ranaconitine isolated from Aconitum sinomontanum Nakai has been determined by single crystal X-ray diffraction analysis. The crystal presents a monoclinic system, space group C2 with Z = 4, unit cell dimensions a = 30.972(19) Å, b = 7.688(5) Å, and c = 19.632(12) Å. Moreover, the intermolecular O–H···O hydrogen bonds and weak π-π interactions play a critical role in expanding the dimensionality.

scholarly journals The reaction of 3,5-diphenyl-1,2-dithiolium-4-olate with aniline: the crystal structure of 1-phenylimino-2-phenylamino-3-phenylindene

1987 ◽  
Vol 65 (12) ◽  
pp. 2830-2833 ◽  
Author(s):  
David M. McKinnon ◽  
Peter D. Clark ◽  
Robert O. Martin ◽  
Louis T. J. Delbaere ◽  
J. Wilson Quail
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Single Crystal ◽  
Least Squares ◽  
Direct Methods ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cell Dimensions ◽  
Unit Cell Dimensions

3,5-Diphenyl-1,2-dithiolium-4-olate (1) reacts with aniline to form 1-phenylimino-2-phenylamino-3-phenylindene (3a). Under suitable conditions, 6-phenylbenzo[b]indeno[1,2-e]-1,2-thiazine is also formed. These structures are confirmed by alternative syntheses. The molecular structure of 3a has been determined by single crystal X-ray diffraction. Compound 3a crystallizes in the monoclinic space group C2/c with unit cell dimensions a = 20.777(3) Å, b = 6.130(3) Å, c = 31.327(3) Å, 3 = 99.59(1)°, and Z = 8. The structure was solved by direct methods and refined by least squares to a final R = 0.055. The molecular structure of 3a shows the three phenyl containing substituents to have the planes of their ring systems tilted between 40° and 60° from the plane of the indene system due to steric repulsions.

X-Ray and Optical Data for a Vanadium-rich Dravite from Silver Knob, Mariposa County, California, U.S.A.

1992 ◽  
Vol 7 (4) ◽  
pp. 236-238 ◽  
Author(s):  
Franklin F. Foit
Keyword(s):  
Diffraction Pattern ◽  
Powder Diffraction ◽  
Divalent Cation ◽  
Optical Data ◽  
Cation Substitution ◽  
X Ray ◽  
Octahedral Sites ◽  
Cell Dimensions ◽  
Compositional Variability ◽  
Unit Cell Dimensions

AbstractX-ray powder diffraction and optical data are presented for a vanadium-rich dravite from Silver Knob, Mariposa County, California, U.S.A. The limited compositional variability observed for vanadium-rich dravite is due to the presence of a Tschermaks substitution whereby the substitution of Al for Si in the tetrahedral ring is charge balanced by trivalent for divalent cation substitution in the octahedral sites in the structure. Vanadium-rich dravite is uniaxial negative with ε = 1.646(2) and ω = 1.676(2). Refined unit cell dimensions are a = 15.9599(10) and c = 7.1889(2); F30 = 111(0.009; 30); M20 = 80; and Dx = 3.07. An indexed X-ray powder diffraction pattern is also presented.

scholarly journals Synthesis, Crystal Structure, and DFT Calculations of 1,3-Diisobutyl Thiourea

2015 ◽  
Vol 2015 ◽  
pp. 1-5 ◽  
Author(s):  
Ataf A. Altaf ◽  
Adnan Shahzad ◽  
Zarif Gul ◽  
Sher A. Khan ◽  
Amin Badshah ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Dft Calculations ◽  
Single Crystal ◽  
Crystal Packing ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cell Dimensions ◽  
Unit Cell Dimensions ◽  
Model Support

1,3-Diisobutyl thiourea was synthesized and characterized by single crystal X-ray diffraction. It gives a monoclinic (α=γ= 90 andβ  ≠90) structure with the space group P21/c. The unit cell dimensions area= 11.5131 (4) Å,b= 9.2355 (3) Å,c= 11.3093 (5) Å,α= 90°,β= 99.569° (2),γ= 90°,V= 1185.78 (8) Å3, andZ= 4. The crystal packing is stabilized by intermolecular (N–H⋯S) hydrogen bonding in the molecules. The optimized geometry and Mullikan's charges of the said molecule calculated with the help of DFT using B3LYP-6-311G model support the crystal structure.

Andymcdonaldite (Fe3+2Te6+O6), a new ferric iron tellurate with inverse trirutile structure from the Detroit district, Juab County, Utah

2020 ◽  
Vol 58 (1) ◽  
pp. 85-97
Author(s):  
Mark F. Coolbaugh ◽  
John K. McCormack ◽  
Mati Raudsepp ◽  
Edith Czech ◽  
Rhy McMillan ◽  
...  
Keyword(s):  
Ferric Iron ◽  
Natural Occurrence ◽  
Synthetic Analogue ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cell Dimensions ◽  
Brownish Black ◽  
A Site ◽  
Unit Cell Dimensions ◽  
Black Color

ABSTRACT Andymcdonaldite is a new ferric-iron-tellurate mineral that occurs within Au-, Te-, and Bi-rich jasperoid at the Wildcat prospect in the Detroit district, Juab County, Utah. The mineral has a yellow-brown to brownish-black color, occurs as extremely cryptocrystalline (11–25 nm) material in thin films and breccia matrix fillings, and is associated with gold (native), tellurium (native), beyerite, clinobisvanite, and a variety of tellurium oxysalt minerals that include carlfriesite, eckhardite, frankhawthorneite, khinite, mcalpineite, paratellurite, tellurite, tlapallite, and xocolatlite. This is the first known natural occurrence of a phase with an ordered (tetragonal) inverse trirutile structure (A3+2B6+O6) which has many synthetic representatives. The B site in andymcdonaldite is occupied by Te and the A site is dominated by Fe with up to approximately 14 mole% substitution by other cations. An empirical formula of (Fe1.74Cu0.12Mn0.06Al0.05Mg0.05)Σ2.02Te1.01O6 was obtained from electron microprobe analyses. Powder X-ray diffraction data, Raman spectra, and unit-cell dimensions for andymcdonaldite strongly resemble those for the synthetic analogue, Fe3+2Te6+O6. The strongest X-ray diffraction lines are [dobsÅ(Iobs)(hkl)]: 4.14(27)(101), 3.28(100)(110), 2.54(71)(103), 1.71(72)(213), and 1.37(39)(303,116). The strongest Raman bands are at 748, 643, and 417 cm–1. The space group is P42/mnm and the cell dimensions are a 4.622–4.630 Å, c 9.077–9.087 Å, and V = 193.94–194.80 Å3 (Z = 2).

Cluster Chemistry. XLVII. X-Ray Crystal Structure of OsPt2(μ-CO)3(CO)2(PPh3)3

1986 ◽  
Vol 39 (12) ◽  
pp. 2145 ◽  
Author(s):  
MI Bruce ◽  
MR Snow ◽  
ERT Tiekink
Keyword(s):  
Crystal Structure ◽  
X Ray Diffraction ◽  
Cluster Chemistry ◽  
Triclinic Space Group ◽  
X Ray ◽  
Metal Atoms ◽  
Metal Metal ◽  
Cell Dimensions ◽  
Unit Cell Dimensions ◽  
Triphenylphosphine Ligand

The crystal structure of OsPt2(μ-CO)3(CO)2(PPh3)3 has been determined by single-crystal X-ray diffraction techniques. Crystals are triclinic, space group Pī with unit cell dimensions a 13.593(4), b 15.839(4), c 12.633(8) Ǻ, α 102.97(3), β 108.18(2), γ 84.86(3)° with Z2. The structure was refined by a full-matrix least-squares procedure on 5896 reflections [I ≥ 2.5σ(I)] to final R 0.028 and Rw 0.034. A triphenylphosphine ligand binds each of the metal atoms disposed at the corners of a triangle. Each metal-metal bond is spanned by a bridging carbonyl group. The coordination about the osmium atom is completed by two terminal carbonyl groups.

Structural study in the oligomethylene dithiobenzoate series, nDBS, where n, the number of methylene groups, is odd

1992 ◽  
Vol 70 (3) ◽  
pp. 900-909 ◽  
Author(s):  
Claude Leblanc ◽  
François Brisse
Keyword(s):  
Crystal Structure ◽  
X Ray Diffraction ◽  
Aromatic Rings ◽  
Monoclinic System ◽  
X Ray ◽  
Cell Dimensions ◽  
Unit Cells ◽  
Methylene Groups ◽  
Unit Cell Dimensions ◽  
Centrosymmetric Dimers

Model compounds of the poly(oligomethylene thioterephthalates) have been synthesized and characterized by X-ray diffraction analyses. The pink n-methylenedithiobenzoates, obtained for n = 3, 5, 7, and 9, all have a low melting point of about 320–330 K. They all crystallize in the monoclinic system, space group P21/c. The a and b unit cell dimensions vary little while the c dimension increases monotonically as n changes from 3 to 9. The crystal structure of the four compounds were established from low-temperature X-ray intensities. Except for the lengthening of the methylenic sequence, the four molecules studied here are isostructural. One of the thiobenzoate groups of the molecules is coplanar with all the methylenic carbons, while the other thiobenzoate group is at 90° from the above plane of atoms. The methylenic sequence has the same conformation. It may be described by g+(t)n, where n is the number of methylene groups. Thus, the four compounds belong to a crystallographically homologous series. The molecules form centrosymmetric "dimers," which, in turn, are herring-bone packed in their respective unit cells. In each "dimmer" two aromatic rings are across from one another while being mutually perpendicular. On the basis of the above results, one proposes three potentially acceptable structures for the parent poly(oligomethylene thioterephthalates). Keywords: dithiobenzoate, methylene sequence, crystal structure, poly(oligomethylene thioterephthalate).

Crystal structure of Al5O3N3 (15R)

2017 ◽  
Vol 32 (S1) ◽  
pp. S2-S5 ◽  
Author(s):  
Jacek Podwórny ◽  
Alicja Pawełek ◽  
Jerzy Czechowski
Keyword(s):  
Crystal Structure ◽  
Structure Determination ◽  
Structural Model ◽  
Stoichiometric Composition ◽  
Unit Cell ◽  
Second Phase ◽  
Space Group ◽  
X Ray ◽  
Cell Dimensions ◽  
Unit Cell Dimensions

Having synthesised an AlON-bonded ceramic corundum material, Al5O3N3 (15R) polytype coexisting with α-Al2O3 was identified. The sample was prepared from an alumina-rich mixture of Al2O3 and AlN substrates and fired at 1650 °C in a nitrogen atmosphere. Using the X-ray external standard quantitative method, one of the reaction products, α-Al2O3, was quantified. From the remaining substrates the stoichiometric composition of the second phase was calculated. The applied method of crystal structure determination consisted of three stages. In the first stage, the Le Bail method of X-ray pattern decomposition was used for the extraction of Al5O3N3 (15R) diffraction lines from a two-phase diffractogram. The space group and unit-cell dimensions from the isostructural SiAl4O2N4 SiAlON phase, producing the same X-ray pattern, were used as input data. Next, the direct structure determination in real space was applied for initial structural model derivation, which was followed by Rietveld refinement. The solved crystal structure of Al5O3N3 (15R), except the stacking sequence, proved to be closely related to the structure of Al7O3N5 (21R) polytype. The Al5O3N3 (15R) is trigonal with space group R-3m, unit-cell dimensions a0 = 3.0128 Å, c0 = 41.8544 Å, and volume V = 329.00 Å3. The model of Al5O3N3 (15R) polytype structure has positional disordering in one of three (6c) Al sites, which leads to stacking faults in six tetrahedral layers. Every third tetrahedron from LR3 and LR4, LR8 and LR9, LR13 and LR14 layers is rotated by 180°.

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