scholarly journals Crystallography of Vanadium-bearing Micas (Bol'shoi Karatau Range, Kazakhstan)

2014 ◽  
Vol 70 (a1) ◽  
pp. C1102-C1102
Author(s):  
Galiya Bekenova ◽  
Kulyash Dyussembayeva
Keyword(s):  
Crystal Structure ◽  
Cell Parameter ◽  
Structural Characteristics ◽  
Structural Parameters ◽  
Vanadium Content ◽  
Polished Section ◽  
X Ray ◽  
North West ◽  
Mineralogical Study ◽  
Crystal Structural

The mineralogical study of vanadium and vanadium-bearing micas from Cambrian carbonaceous-cherty formation of North-West of Bol'shoi Karatau range has allowed to establish four basic groups: 1. chernykhite (V2O3+V2O4 up to 23%); 2. Ba-roscoelite (V2O3 up to 18%) [1]; 3. vanadium-bearing muscovite and phengite (V2O3 up to 5%) and 4. secondary mica – V-Ba-phengite (V2O3+V2O4 up to 6-8%) [2]. Physical, optical properties as well as crystal structural parameters depend on vanadium content. The crystal structure of micas was determined by X-ray and electron diffraction techniques. The polytypes and unit cell parameter b (Å) are the main structural characteristics [3]. 2M1 polytype is spread among vanadium micas. Polytypes 1M and (1M+2M1) are only in vanadium-bearing micas – muscovite and phengite. The minimum b 9.03-9.04 Å is typical for this group. For secondary mica - V-Ba-phengite the parameter b varies from 9.6 to 9.09 Å. On the figure the secondary mica (1) is associated with mica without vanadium (2) and carbon-clay-chert (3) into polished section, where epoxy resin (4). For Ba-roscoelite b is equal 9.07-9.15 Å; for chernykhite - b 9.18 Å.

scholarly journals Linear Structural Trends and Multi-Phase Intergrowths in Helvine-Group Minerals, (Zn,Fe,Mn)8[Be6Si6O24]S2

Minerals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 325
Author(s):  
Sytle Antao
Keyword(s):  
Cell Parameter ◽  
Structural Parameters ◽  
Unit Cell ◽  
Fluid Composition ◽  
Ternary Solid Solution ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Difference ◽  
Multi Phase ◽  
And Diffusion

Synchrotron high-resolution powder X-ray diffraction (HRPXRD) and Rietveld structure refinements were used to examine the crystal structure of single phases and intergrowths (either two or three phases) in 13 samples of the helvine-group minerals, (Zn,Fe,Mn)8[Be6Si6O24]S2. The helvine structure was refined in the cubic space group P4¯3n. For the intergrowths, simultaneous refinements were carried out for each phase. The structural parameters for each phase in an intergrowth are only slightly different from each other. Each phase in an intergrowth has well-defined unit-cell and structural parameters that are significantly different from the three endmembers and these do not represent exsolution or immiscibility gaps in the ternary solid-solution series. The reason for the intergrowths in the helvine-group minerals is not clear considering the similar radii, identical charge, and diffusion among the interstitial M cations (Zn2+, Fe2+, and Mn2+) that are characteristic of elongated tetrahedral coordination. The difference between the radii of Zn2+ and Mn2+ cations is 10%. Depending on the availability of the M cations, intergrowths may occur as the temperature, pressure, fugacity fS2, and fluid composition change on crystallization. The Be–Si atoms are fully ordered. The Be–O and Si–O distances are nearly constant. Several structural parameters (Be–O–Si bridging angle, M–O, M–S, average <M–O/S>[4] distances, and TO4 rotational angles) vary linearly with the a unit-cell parameter across the series because of the size of the M cation.

Preparation and crystal structure of garnet-type calcium zirconium germanate Ca4ZrGe3O12

2016 ◽  
Vol 31 (4) ◽  
pp. 292-294 ◽  
Author(s):  
V. D. Zhuravlev ◽  
A. P. Tyutyunnik ◽  
N. I. Lobachevskaya
Keyword(s):  
Crystal Structure ◽  
Unit Cell Parameter ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Cell Parameter ◽  
Polycrystalline Sample ◽  
Structural Formula ◽  
Powder Diffraction Data ◽  
Structural Refinement ◽  
X Ray

A polycrystalline sample of Ca4ZrGe3O12 was synthesized using the nitrate–citrate method and heated at 850–1100 °C. Structural refinement based on X-ray powder diffraction data showed that the crystal structure is of the garnet type with a cubic unit-cell parameter [a = 12.71299(3) Å] and the space group Ia$\bar 3$d. The structural formula is presented as Ca3[CaZr]octa[Ge]tetraO12.

scholarly journals X-ray Single-Crystal Structural Analysis of a Magnetically Oriented Monoclinic Microcrystal Suspension of α-Glycine

Crystals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 561 ◽  
Author(s):  
Tatsuya Tanaka ◽  
Chiaki Tsuboi ◽  
Kazuaki Aburaya ◽  
Fumiko Kimura ◽  
Masataka Maeyama ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Magnetic Susceptibility ◽  
Single Crystal ◽  
Magnetic Energy ◽  
Powder Sample ◽  
Single Crystal Structure ◽  
X Ray ◽  
Crystal Structural ◽  
The Relationship ◽  
Good Agreement

We previously reported on a method for X-ray single-crystal structure determination from a powder sample via a magnetically oriented microcrystal suspension (MOMS). The method was successfully applied to orthorhombic microcrystals (L-alanine, P212121). In this study, we apply this method to monoclinic microcrystals. Unlike most of the orthorhombic MOMSs, monoclinic MOMSs exhibit two or four orientations with the same magnetic energy (we refer to this as twin orientations), making data processing difficult. In this paper, we perform a MOMS experiment for a powder sample of monoclinic microcrystal (α-glycine, P21/n) to show that our method can also be applied to monoclinic crystals. The single-crystal structure determined in this work is in good agreement with the reported one performed on a real single crystal. Furthermore, the relationship between the crystallographic and magnetic susceptibility axes is determined.

scholarly journals (AsPh4)4[CrCl4(μ-N2S2)]4 · 8 CH2Cl2; Synthese, IR-Spektrum und Kristallstruktur / (AsPh4)4[CrCl4(μ-N2S2)]4 · 8 CH2Cl2; Synthesis, IR Spectrum and Crystal Structure

1985 ◽  
Vol 40 (10) ◽  
pp. 1314-1319 ◽  
Author(s):  
Heribert Wadle ◽  
Kurt Dehnicke ◽  
Dieter Fenske
Keyword(s):  
Crystal Structure ◽  
Major Product ◽  
X Ray ◽  
Lattice Constants ◽  
Chromium Hexacarbonyl ◽  
Distorted Octahedral Coordination ◽  
Chromium Vi ◽  
Distorted Octahedral ◽  
Tetraphenylarsonium Chloride ◽  
Crystal Structural

Trithiazylchloride, (NSCl)3, reacts with metallic chromium, with chromium hexacarbonyl, with CrCl3·3 thf, as well as with chromium(VI) oxide to form mixtures, in which S4N3⊕ [CrCl4(N2S2)]⊖ can be identified as the major product. This compound reacts with tetraphenylarsonium chloride in dichloromethane to form the title compound, which we have characterized by IR spectroscopy and an X-ray crystal structural analysis. (AsPh4)4[CrCl4(N2S2)]4·8 CH2Cl2 crystallizes monoclinically in the space group C2/c with four formula units per unit cell and with the following lattice constants at -100 °C: a = 2146, b = 2033, c = 3137 pm; β = 96.0° (9918 independent observed reflexions, R = 0.064). The compound consists of AsPh4⊕ ions, tetrameric anions [CrCl4(N2S2)]44⊖ and included CH2Cl2 molecules. The chromium atoms of the anions occupy the corners of a nearly ideal square; they are connected via the N-atoms of planar N2S2-rings, which are oriented perpendicularly to the Cr4-plane. The chromium atoms complete their distorted octahedral coordination with four terminal chlorine atoms, the axial ones of which form short Cl···S-contacts of average 310 pm to the S-atoms of the N2S2-rings.

Cation distribution in natural Zn-aluminate spinels

1998 ◽  
Vol 62 (1) ◽  
pp. 41-54 ◽  
Author(s):  
S. Lucchesi ◽  
A. Della Giusta ◽  
U. Russo
Keyword(s):  
Cation Distribution ◽  
Cell Parameter ◽  
Formula Unit ◽  
Tetrahedral Coordination ◽  
Structural Refinement ◽  
Interatomic Distances ◽  
X Ray ◽  
Crystal Structural ◽  
Cation Distributions

AbstractThe intracrystalline cation distributions in fourteen natural Zn-aluminate spinels were determined by means of X-ray single-crystal structural refinement, supported for some samples by Mössbauer spectroscopy.Zinc substitutes for Mg and subordinately Fe2+ and its relevant changes in content, from 0.10 to 0.96 atoms per formula unit (apfu), are not related to variations of cell parameter. The latter is determined mainly by the substitution Fe3+ ⇌ Al. In agreement with data from synthetic samples, a small but definite amount of Zn (up to 0.06 apfu) is located in the octahedral M site. Fe2+, when present, shows a preference for tetrahedral coordination.An improved value of the tetrahedral Zn(T)-O distance (1.960 Å) was obtained, integrating the set of interatomic distances used for the determination of cation distribution in spinels.

A novel self-complementary three-dimensional inorganic network organized by H-bond dimers of inorganic chains — Synthesis and crystal structure of (C6H16N2)[Zn(HPO4)2]

2004 ◽  
Vol 82 (5) ◽  
pp. 616-621 ◽  
Author(s):  
Xian-Ming Zhang ◽  
Chan-Juan Bai ◽  
Yan-Li Zhang ◽  
Hai-Shun Wu
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Three Dimensional ◽  
Synthesis And Crystal Structure ◽  
X Ray ◽  
Crystal Structural ◽  
Inorganic Framework ◽  
Phosphate Groups ◽  
Inorganic Network

A novel organic-templated zincophosphate, namely (C6H16N2)[Zn(HPO4)2], was hydrothermally synthesized and X-ray single-crystal structural analysis reveals that the anions [Zn(HPO4)2]2–, which have square-twisted chains containing corner-sharing four-rings of alternating ZnO4 and PO4 tetrahedra, are assemblied via self-complementary strong and symmetrical hydrogen-bonding R22(8) synthons between the phosphate groups into three-dimensional hydrogen bond frameworks featuring three-dimensional intersecting pseudochannels. The doubly protonated 2,5-dimethylpiperazinium cations are attached to the three-dimensional inorganic framework via N-H···O hydrogen bonds to strengthen the 3-D network.

About the crystal structure of La1−xSrxCoO3−δ (0≤x≤0.6)

1996 ◽  
Vol 11 (1) ◽  
pp. 31-34 ◽  
Author(s):  
Nicole M. L. N. P. Closset ◽  
René H. E. van Doorn ◽  
Henk Kruidhof ◽  
Jaap Boeijsma
Keyword(s):  
Crystal Structure ◽  
Unit Cell Parameter ◽  
Cell Parameter ◽  
Unit Cell ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Cell Parameters

The crystal structure of La1−xSrxCoO3−δ (0≤x≤0.6) has been studied, using powder X-Ray diffraction. The crystal structure shows a transition from rhombohedral distorted perovskite for LaCoO3−δ into cubic perovskite for La0.4Sr0.6CoO3−δ. The cubic unit cell parameter is ac=3.8342(1) Å for La0.4Sr0.6CoO3−δ, the space group probably being Pm3m. Using a hexagonal setting, the cell parameters for La0.5Sr0.5CoO3−δ, are a=5.4300(3) Å, c=13.2516(10) Å; a=5.4375(1) Å, c=13.2313(4) Å for La0.6Sr0.4CoO3−δ; a=5.4437(1) Å, c=13.2085(5) Å for La0.7Sr0.3CoO3−δ; a=5.4497(2) Å, c=13.1781(6) Å for La0.8Sr0.2CoO3−δ and a=5.4445(2) Å, c=13.0936(6) Å for LaCoO3−δ with the space group probably being R3c.

X-Ray Standing Wave and High Resolution Diffraction Study of Si/Ge Superlattices

1995 ◽  
Vol 379 ◽  
Author(s):  
S. Lagomarsino ◽  
P. Castrucci ◽  
P. Calicchia ◽  
A. Cedola ◽  
A. Kazimirov
Keyword(s):  
High Resolution ◽  
Standing Wave ◽  
Structural Characteristics ◽  
Structural Parameters ◽  
Phase 1 ◽  
Modern Technology ◽  
Characterization Methods ◽  
X Ray ◽  
Optimal Behavior ◽  
Strong Reflection

ABSTRACTIn modern technology more and more attention is given to epitaxial superlattices. III/V, and more recently Si/Ge superlattices are widely studied because of their applications in integrated optoelectronics. Since the physical properties are strongly dependent on structural characteristics, it is evident that accurate characterization methods are required in order to improve their quality and obtain optimal behavior. X-ray high resolution diffraction is extensively and successfully used to this purpose. In general diffracted intensity is measured close to strong substrate reflections where satellite peaks from superlattice take place. If the crystalline quality, mainly concerning thickness layer uniformity and interface abruptness is good, several orders of diffraction from the superlattice are visible, and fitting based on kinematical or dynamical diffraction can provide information about many structural parameters of the superlattice. However from diffracted intensity the information about the phase of the structure factor is lost. It is well known that the X-ray Standing Wave (XSW) technique can provide direct information about the phase [1]. In this paper we present measurements and calculations relative to the extension of the XSW method to the study of MBE-grown Si/Ge superlattices. The novelty consists in using the superlattice satellite peaks close to a strong reflection from the substrate to form the standing wave field which in turn excites the atoms whose fluorescence is measured. These satellite peaks correspond to high-order diffraction for the superlattice periodicity.

Structure and Magnetic Properties of (Cr,Ni)4-xCoxSi

2019 ◽  
Vol 289 ◽  
pp. 108-113
Author(s):  
Romana Iryna Martyniak ◽  
Nataliya Muts ◽  
Olga Sichevych ◽  
Horst Borrmann ◽  
Matej Bobnar ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Cell Parameter ◽  
Powder Diffraction Data ◽  
X Ray ◽  
Pearson Symbol ◽  
Paramagnetic Behaviour

The crystal structure of the (Cr,Ni)4Si phase with and without Co was refined from X-ray powder diffraction data. The compound crystallises with an Au4Al-type structure (Pearson symbol cP20, space group P213): unit-cell parameter a = 0.611959(6) nm for the composition (Cr0.312Ni0.688)4Si, a = 0.612094(6) nm for (Cr0.375Ni0.625)4Si, and a = 0.612316(6) nm for (Cr0.337Co0.063Ni0.600)4Si. The magnetic susceptibility was measured in external fields up to 7 T at temperatures between 1.8 and 400 K. The three investigated samples exhibited paramagnetic behaviour described by the modified Curie-Weiss law: χ0 = 146∙10-6 emu g-at.-1, μeff = 0.21 μB/atom, θP = -13 K for (Cr0.312Ni0.688)4Si; χ0 = 158∙10-6 emu g-at.-1, μeff = 0.20 μB/atom, θP = -15 K for (Cr0.375Ni0.625)4Si; χ0 = 169∙10-6 emu g-at.-1, μeff = 0.18 μB/atom, θP = -52 K for (Cr0.337Co0.063Ni0.600)4Si.

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