Raman Spectroscopic and X-ray Diffraction Studies on Concentrated Aqueous Zinc (II) Bromide Solution at High Temperatures

1992 ◽  
Vol 47 (3) ◽  
pp. 485-492 ◽  
Author(s):  
Toshiyuki Takamuku ◽  
Mikito Ihara ◽  
Toshio Yamaguchi ◽  
Hisanobu Wakita
Keyword(s):  
Diffraction Data ◽  
Broad Band ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Raman Spectroscopic ◽  
X Ray Scattering ◽  
Bromide Solution ◽  
Stretching Vibration ◽  
Increasing Temperature

Abstract Raman and X-ray scattering experiments have been performed on an aqueous zinc (II) bromide solution with molar ratio [ H2 0] / [ ZnBr2 ] =10 at 25 to 140 °C. The intensity of the totally symmetric Zn - Br stretching vibration (ν1) for the dibromozinc(II) complex increased with increasing temperature while that for the tetrabromo complex decreased. A broad band assigned to the symmetric Zn - O stretching vibration ( ν1 ) for the aqua zinc (II) ion decreased in intensity with increasing temperature. The X-ray diffraction data revealed that the average number of the Zn - Br interactions within the zinc (II) bromo complexes does not change with temperature, whereas the number of Br ··· Br nonbonding interactions within the complexes decreases from 1.8 at 25 °C to 1.5 at 100 °C. From both Raman and X-ray data it is concluded that with increasing temperature the dibromo species is favored, whereas the tetrabromo and aqua zinc(II) species are unstable in the solution. The analysis of the X-ray diffraction data has shown that the mean Zn - Br bond length within the zinc (II) bromo complexes shortens gradually with increasing temperature, accompanied with an increase in the interligand Br ···Br distance. This finding suggests that the Br - Zn - Br bond angle increases with decreasing Zn - Br distance for the lower zinc(II) bromo complexes. The equilibrium shift of the zinc (II) bromo complexes with temperature is discussed on the basis of ion-ion, ion-water, and water-water interactions

scholarly journals STRUCTURE OF NEAREST ENVIRONMENT OF IONS IN AQUEOUS CESIUM IODIDE SOLUTIONS FROM X-RAY DIFFRACTION DATA

2017 ◽  
Vol 60 (7) ◽  
pp. 21
Author(s):  
Pavel R. Smirnov ◽  
Oleg V. Grechin ◽  
Elena A. Voevodina
Keyword(s):  
Aqueous Solutions ◽  
Diffraction Data ◽  
Ion Pairs ◽  
Diffraction Method ◽  
Cesium Iodide ◽  
Distribution Functions ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Quantitative Parameters

Comparatively large amount of works has been devoted to the investigation of the nearest environment of cesium ions in aqueous solutions. But up to date there are no precise quantitative parameters of it. Information about influence of concentration on cesium salts solutions structure is also absent. In order to get the coordination number of Cs+ ion and its dependence on the amount of dissolved salt the set of aqueous solutions of cesium iodide have been studied by X-ray diffraction method in wide concentration range under ambient conditions. Radial distribution functions (RDFs) of the solutions investigated have been calculated from experimental intensity curves of X-ray scattering. Interpretation of experimental peaks on RDFs has been made. On the basis of experimental results and literature information some physically reasonable models of solution have been constructed. Theoretical RDFs have been calculated for every model. Then an optimization procedure has also been made. On the ground of the best fitness between experimental and theoretical RDFs the optimal models for every solution have been found. All quantitative parameters have been tabulated and analyzed. Hydration numbers of Cs+ and I- increase with dilution, reaching in the solution of molar ratio 1:80 values 6.3 and 4.1, respectively. Interparticle distances of Cs+–ОН2 and I- –ОН2 are equal approximately to 0.312 and 0.359 nm. The ions do not form the second coordination shells. It has been determined that contact ion pairs Cs+–I- exist in whole concentration range investigated.Forcitation:Smirnov P.R., Grechin O.V., Voevodina E.A. Structure of nearest environment of ions in aqueous cesium iodide solutions from X-ray diffraction data. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2017. V. 60. N 7. P. 21-26.

Evaluation of the structural model for ferrihydrite derived from real-space modelling of high-energy X-ray diffraction data

Clay Minerals ◽  
2009 ◽  
Vol 44 (1) ◽  
pp. 19-34 ◽  
Author(s):  
A. Manceau
Keyword(s):  
Diffraction Data ◽  
Structural Model ◽  
High Energy ◽  
Real Space ◽  
Structural Motif ◽  
X Ray Diffraction ◽  
X Ray ◽  
X Ray Scattering ◽  
Crystal Electron ◽  
Tetrahedral Iron

AbstractA new structural model for ferrihydrite that challenges the standard ferrihydrite model established by X-ray diffraction and confirmed by neutron diffraction and single-crystal electron nanodiffraction was recently proposed by Michel et al. (2007a) from the simulation of the pair distribution function obtained by Fourier transformation of diffraction data measured at λ = 0.137 Å. The new ferrihydrite model is isostructural to akdalaite (Al10O14(OH)2), a mineral having the Baker-Figgis δ-isomer of the Al13-Keggin structure as its structural motif. The new model is unrealistic because: (1) it is completely periodic (i.e. defect-free); (2), it has 20% tetravalent octahedral iron (VIFe4+), 20% divalent tetrahedral iron (IVFe2+), and some IVFe–O distances equal to or larger than the VIFe3+–O distances, thus violating Pauling's 2nd rule; (3) it does not describe X-ray diffraction and EXAFS spectroscopic data; and, (4) it is inconsistent with electron microscopy results and contradicts previous X-ray scattering studies.

Synthesis, structural characterization, and hydrogen bonds of Co9(OH)14[SO4]2

2017 ◽  
Vol 72 (7) ◽  
pp. 505-510
Author(s):  
Hamdi Ben Yahia ◽  
Masahiro Shikano ◽  
Ilias Belharouak
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Single Crystal ◽  
Structural Characterization ◽  
Diffraction Data ◽  
Atmospheric Oxygen ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Triclinic System

AbstractThe new compound Co9(OH)14[SO4]2 was synthesized using a hydrothermal method from LiF, Na2SO3, and Co(CH3COO)2·4H2O in a molar ratio of 1:1:1 in the presence of atmospheric oxygen. Its crystal structure was determined from single crystal X-ray diffraction data. Co9(OH)14[SO4]2 crystallizes in the triclinic system, space group P1̅ with a=7.693(2) Å, b=8.318(2) Å, c=8.351(2) Å, α=82.375(5)°, β=77.832(4)°, γ=68.395(4)°, V=484.8(2) Å3, and Z=2. Its structure is composed of cobalt-containing sheets interconnected by SO4 tetrahedra. Bent and symmetrically trifurcated hydrogen bonds have been observed. Furthermore, structural similarities with hydrozincite and brucite minerals have been noticed.

An X-Ray Diffraction Study on an Aqueous Solution of CdSO4 at 9 and 62 °C

1981 ◽  
Vol 36 (10) ◽  
pp. 1062-1066
Author(s):  
Ruggero Caminiti
Keyword(s):  
Aqueous Solution ◽  
Diffraction Study ◽  
Structural Unit ◽  
Water Molecules ◽  
Liquid Sample ◽  
X Ray Diffraction ◽  
Experimental Distribution ◽  
X Ray ◽  
X Ray Scattering ◽  
Increasing Temperature

The X-Ray scattering of a 2 M aqueous solution CdSO4 has been measured at 9 and 62 °C in a “Θ-Θ” transmission arrangement with a plane-parallel liquid sample. The experimental distribution curves show main peaks at about 1.5, 2.3, 2.8, 3.5, and 4.35 Å. The 3.5 A peak reveals the formation of inner sphere cadmium-sulphate complexes Cd(H2O)6-z(OSO3)z+2-2z, in which oxygens from sulphate groups substitute z water molecules of the hydrated Cd(H2O)62+ ions. Least squares refinements of the i(s) curves are consistent with a structural unit in which the sulphate tetrahedron shares a corner with one cadmium octahedron with Cd-O-S angle of 133 deg. The average number (z) of coordinated sulphate ions increases with increasing temperature.

scholarly journals Crystal structures of synthetic 7 Å and 10 Å manganates substituted by mono- and divalent cations

1994 ◽  
Vol 58 (392) ◽  
pp. 425-447 ◽  
Author(s):  
Kenshi Kuma ◽  
Akira Usui ◽  
William Paplawsky ◽  
Benjamin Gedulin ◽  
Gustaf Arrhenius
Keyword(s):  
Crystal Structures ◽  
Diffraction Data ◽  
Divalent Cations ◽  
Unit Cell ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
Monoclinic Crystal ◽  
X Ray ◽  
Cell Parameters

AbstractThe crystal structures of synthetic 7 Å and 10 Å manganates, synthetic birnessite and buserite, substituted by mono- and divalent cations were investigated by X-ray and electron diffractions. The monoclinic unit cell parameters of the subcell of lithium 7 Å manganate, which is one of the best ordered manganates, were obtained by computing the X-ray powder diffraction data: a = 5.152 Å, b = 2.845 Å, c = 7.196 Å, β = 103.08°. On the basis of the indices obtained by computing the X-ray diffraction data of Li 7 Å manganate, monovalent Na, K and Cs and divalent Be, Sr and Ba 7 Å manganates were interpreted as the same monoclinic structure with β = 100–103° as that of Li 7 Å manganate, from their X-ray diffraction data. In addition, divalent Mg, Ca and Ni 10 Å manganates were also interpreted as the same monoclinic crystal system with β = 90–94° The unit cell parameters, especially a, c and β, change possibly with the type of substituent cation probably because of the different ionic radius, hydration energy and molar ratio of substituent cation to manganese. However, these diffraction data, except for those of Sr and Ba 7 Å and Ca and Ni 10 Å manganates, reveal only some parts of the host manganese structure with the edge-shared [MnO6] octahedral layer. On the other hand, one of the superlattice reflections observed in the electron diffractions was found in the X-ray diffraction lines for heavier divalent cations Sr and Ba 7 Å and Ca and Ni 10 Å manganates. The reflection presumably results from the substituent cation position in the interlayer which is associated with the vacancies in the edge-shared [MnO6] layer and indicates that the essential vacancies are linearly arranged parallel to the b-axis. Furthermore, the characteristic superlattice reflection patterns for several cations, Li, Mg, Ca, Sr, Ba and Ni, manganates were interpreted that the substituent cations are regularly distributed in the interlayer according to the exchange percentage of substituent cation to Na+. In contrast, the streaking in the a-direction observed strongly in the electron diffractions for heavier monovalent cations, K and Cs, manganates probably results from the disordering of their cations in the a-direction in the interlayer.

scholarly journals X-Ray Diffraction and Raman Spectroscopic Studies of Glasses and Glass-Ceramics Inside the A2O-MoO3-Nb2O5-P2O5 (A= Li, Na) Systems

2010 ◽  
Vol 12 (3,4) ◽  
pp. 207
Author(s):  
H. Bih ◽  
L. Bih ◽  
M.P.F. Graça ◽  
M.A. Valente ◽  
B. Elouadi
Keyword(s):  
Glass Ceramics ◽  
Spectroscopic Studies ◽  
Phosphate Glasses ◽  
Molar Ratio ◽  
Thermal Treatments ◽  
X Ray Diffraction ◽  
X Ray ◽  
Raman Spectroscopic ◽  
Heat Treated ◽  
Quenching Method

<p>Phosphate glasses in the system (50-x)A<sub>2</sub>O-xMoO<sub>3</sub>-10Nb<sub>2</sub>O<sub>5</sub>-40P<sub>2</sub>O<sub>5</sub> (AMo-40), with x=0; 30 and A=Li or Na were prepared by the melt quenching method. The effect in the crystallization behaviour of the glass due to the introduction of MoO<sub>3</sub> in the glass composition and varying the molar ratio between network modifiers and network formers (M/F) was studied. The prepared glasses were heat-treated in air, at 550, 600 and 650 ºC for 4 hours. The structure, of the obtained samples, was studied by differential thermal analysis (DTA), X-ray powder diffraction (XRD), Raman spectroscopy and the morphology by scanning electron microscopy (SEM). It was found that the replacement of Li<sub>2</sub>O or Na<sub>2</sub>O by MoO<sub>3</sub> reduces the number of the crystallised phases. In the lithium-niobiophosphate glasses the presence of MoO<sub>3</sub> promotes the formation of NbOPO<sub>4</sub> and reduces the formation of ortho- and pyro-phosphate phases. The thermal treatments affect the arrangements of the network structure of the AMo-40-glasses.</p>

scholarly journals Refinements on electron diffraction data of β-glycine in MoPro: a quest for an improved structure model

2021 ◽  
Vol 54 (4) ◽  
Author(s):  
Kunal Kumar Jha ◽  
Barbara Gruza ◽  
Michał Leszek Chodkiewicz ◽  
Christian Jelsch ◽  
Paulina Maria Dominiak
Keyword(s):  
Electron Diffraction ◽  
Diffraction Data ◽  
Structure Determination ◽  
Structure Refinement ◽  
Electron Diffraction Data ◽  
Bethe Equation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Atom Model ◽  
X Ray Scattering

The advancement in 3D electron diffraction (3D ED) techniques that lead to a revolution in molecular structure determination using nano-sized crystals is now achieving atomic resolution. The structures can be obtained from 3D ED data with tools similar to those used for X-ray structure determination. In this context, the MoPro software, originally designed for structure and charge density refinements using X-ray diffraction data, has been adapted. Structure refinement on 3D ED data was achieved via implementation of electron scattering factors available in the literature and by application of the Mott–Bethe equation to X-ray scattering factors computed from the multipolar atom model. The multipolar model was parametrized using the transferable pseudoatom databanks ELMAM2 and UBDB. Applying the independent atom model (IAM), i.e. spherical neutral atom refinement, to 3D ED data on β-glycine in MoPro resulted in structure and refinement statistics comparable to those obtained from other well known software. Use of the transferred aspherical atom model (TAAM) led to improvement of the refinement statistics and a better fit of the model to the 3D ED data as compared with the spherical atom refinement. The anisotropic displacement parameters of non-H atoms appear underestimated by typically 0.003 Å2 for the non-H atoms in IAM refinement compared with TAAM. Thus, MoPro is shown to be an effective tool for crystal structure refinement on 3D ED data and allows use of a spherical or a multipolar atom model. Electron density databases can be readily transferred with no further modification needed when the Mott–Bethe equation is applied.

New Structure of CTAB Templated Silica Films as revealed by GISAXS coupled to HRTEM

2000 ◽  
Vol 628 ◽  
Author(s):  
Sophie Besson ◽  
Catherine Jacquiod ◽  
Thierry Gacoin ◽  
André Naudon ◽  
Christian Ricolleau ◽  
...  
Keyword(s):  
Cetyltrimethylammonium Bromide ◽  
Grazing Incidence ◽  
Hexagonal Structure ◽  
X Ray Diffraction ◽  
Electronic Microscopy ◽  
Silica Films ◽  
X Ray ◽  
X Ray Scattering ◽  
Hexagonal Arrangement ◽  
Spherical Micelles

ABSTRACTA microstructural study on surfactant templated silica films is performed by coupling traditional X-Ray Diffraction (XRD) and Transmission Electronic Microscopy (TEM) to Grazing Incidence Small Angle X-Ray Scattering (GISAXS). By this method it is shown that spin-coating of silicate solutions with cationic surfactant cetyltrimethylammonium bromide (CTAB) as a templating agent provides 3D hexagonal structure (space group P63/mmc) that is no longer compatible with the often described hexagonal arrangement of tubular micelles but rather with an hexagonal arrangement of spherical micelles. The extent of the hexagonal ordering and the texture can be optimized in films by varying the composition of the solution.

Sign in / Sign up

Export Citation Format

Share Document