scholarly journals On the Structure in Aqueous Superconcentrated Calcium Nitrate

1981 ◽  
Vol 36 (8) ◽  
pp. 831-835 ◽  
Author(s):  
R. Caminiti ◽  
A. Musinu ◽  
G. Paschina ◽  
G. Piccaluga ◽  
G. Pinna
Keyword(s):  
Experimental Data ◽  
Calcium Ions ◽  
Calcium Nitrate ◽  
Water Molecules ◽  
X Ray Diffraction ◽  
X Ray ◽  
Crystalline Hydrates ◽  
Oxygen Atoms

Abstract Liquid hydrous calcium nitrate of composition Ca(NO3)2 · 3.5 H2O was investigated by X-ray diffraction. Experimental data were interpreted in terms of geometrical models suggested by the structure of the crystalline hydrates Ca (NO3)2 · 3H2O and Ca(NO3)2 · 4H2O, in which calcium ions are coordinated to nine oxygen atoms, partly coming from water molecules, partly from NO3-ions.

scholarly journals Synthesis and Complexation Properties of 2-Hydroxy-5-methoxyphenylphosphonic Acid (H3L1). Crystal Structure of the [Cu(H2L1)2(Н2О)2] Complex

2021 ◽  
Vol 91 (11) ◽  
pp. 2176-2186
Author(s):  
G. S. Tsebrikova ◽  
Yu. I. Rogacheva ◽  
I. S. Ivanova ◽  
A. B. Ilyukhin ◽  
V. P. Soloviev ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Methoxy Group ◽  
Protonation Constants ◽  
Water Molecules ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Stability ◽  
Intramolecular Hydrogen ◽  
Oxygen Atoms

Abstract 2-Hydroxy-5-methoxyphenylphosphonic acid (H3L1) and the complex [Cu(H2L1)2(H2O)2] were synthesized and characterized by IR spectroscopy, thermogravimetry, and X-ray diffraction analysis. The polyhedron of the copper atom is an axially elongated square bipyramid with oxygen atoms of phenolic and of monodeprotonated phosphonic groups at the base and oxygen atoms of water molecules at the vertices. The protonation constants of the H3L1 acid and the stability constants of its Cu2+ complexes in water were determined by potentiometric titration. The protonation constants of the acid in water are significantly influenced by the intramolecular hydrogen bond and the methoxy group. The H3L1 acid forms complexes CuL‒ and CuL24‒ with Cu2+ in water.

scholarly journals Molecular Dynamics Modellization and Simulation of Water Diffusion through Plant Cutin

1999 ◽  
Vol 54 (11) ◽  
pp. 896-902 ◽  
Author(s):  
Antonio Matas ◽  
Antonio Heredia
Keyword(s):  
Experimental Data ◽  
Molecular Dynamics ◽  
Structural Information ◽  
Md Simulations ◽  
Water Molecules ◽  
Plant Cuticle ◽  
X Ray Diffraction ◽  
Cross Link ◽  
X Ray ◽  
Good Agreement

Abstract A theoretical molecular modelling study has been conducted for cutin, the biopolyester that forms the main structural component of the plant cuticle. Molecular dynamics (MD) simulations, extended over several ten picoseconds, suggests that cutin is a moderately flexible netting with motional constraints mainly located at the cross-link sites of functional ester groups. This study also gives structural information essentially in accordance with previously reported experimental data, obtained from X -ray diffraction and nuclear magnetic resonance experiments. MD calculations were also performed to simulate the diffusion of water mole­cules through the cutin biopolymer. The theoretical analysis gives evidence that water perme­ation proceedes by a “hopping mechanism”. Coefficients for the diffusion of the water molecules in cutin were obtained from their mean-square displacements yielding values in good agreement with experimental data.

Identification of a deleterious phase in photocatalyst based on Cd1 − xZnxS/Zn(OH)2by simulated XRD patterns

2017 ◽  
Vol 73 (3) ◽  
pp. 360-368 ◽  
Author(s):  
Svetlana Cherepanova ◽  
Dina Markovskaya ◽  
Ekaterina Kozlova
Keyword(s):  
Experimental Data ◽  
Thermogravimetric Analysis ◽  
Variable Temperature ◽  
Interlayer Distance ◽  
Water Molecules ◽  
X Ray Diffraction ◽  
Xrd Pattern ◽  
X Ray ◽  
Diffraction Peaks ◽  
Xrd Patterns

The X-ray diffraction (XRD) pattern of a deleterious phase in the photocatalyst based on Cd1 − xZnxS/Zn(OH)2contains two relatively intense asymmetric peaks withd-spacings of 2.72 and 1.56 Å. Very small diffraction peaks with interplanar distances of (d) ≃ 8.01, 5.40, 4.09, 3.15, 2.49 and 1.35 Å are characteristic of this phase but not always observed. To identify this phase, the XRD patterns for sheet-like hydroxide β-Zn(OH)2and sheet-like hydrozincite Zn5(CO3)2(OH)6as well as for turbostratic hydrozincite were simulated. It is shown that the XRD pattern calculated on the basis of the last model gives the best correspondence with experimental data. Distances between layers in the turbostratically disordered hydrozincite fluctuate aroundd≃ 8.01 Å. This average layer-to-layer distance is significantly higher than the interlayer distance 6.77 Å in the ordered Zn5(CO3)2(OH)6probably due to a deficiency of CO32−anions, excess OH−and the presence of water molecules in the interlayers. It is shown by variable-temperature XRD and thermogravimetric analysis (TGA) that the nanocrystalline turbostratic nonstoichiometric hydrozincite-like phase is quite thermostable. It decomposes into ZnO in air above 473 K.

scholarly journals X-ray structure of 1D-coordination polymer of copperII bearing 1,4-pyrazine-2,3-dicarboxylic acid and 2-aminopyrimidine

2012 ◽  
Vol 77 (1) ◽  
pp. 67-73 ◽  
Author(s):  
Masoud Mirzaei ◽  
Hossein Eshtiagh-Hosseini ◽  
Azam Hassanpoor ◽  
Victor Barba
Keyword(s):  
Coordination Polymer ◽  
Dicarboxylic Acid ◽  
Supramolecular Assembly ◽  
Axial Position ◽  
Water Molecules ◽  
X Ray Diffraction ◽  
Double Chain ◽  
X Ray ◽  
1D Coordination Polymer ◽  
Oxygen Atoms

The new 1D-coordination polymer of CuII ion, {(2- apymH)2[Cu(pyzdc)2] .6H2O}n, (2-apym = 2-aminopyrimidine, pyzdcH2 = 1,4- pyrazine-2,3-dicarboxylic acid), was synthesized based on proton transfer mechanism and characterized by elemental analysis, infrared spectroscopy, and single crystal X-ray diffraction. The coordination polymer consists of infinite anionic chains of [Cu(pyzdc)2]2- anion bridged crossing double chain running along a-axis and discrete (2-apymH)+ fragment. The CuII ion is located on inversion centre in the basal plane of an elongated octahedron and two oxygen atoms from adjacent (pyzdc)2-ligands occupy axial position. The interaction between oxygen atoms of water molecules along with the dicarboxylic acid play an important role in the overall supramolecular assembly.

The crystal structures of sjögrenite and pyroaurite

1967 ◽  
Vol 36 (280) ◽  
pp. 465-479 ◽  
Author(s):  
L. Ingram ◽  
H. F. W. Taylor
Keyword(s):  
Crystal Structures ◽  
Three Dimensional ◽  
Water Molecules ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Approximate Composition ◽  
Oxygen Atoms

SummaryThe crystal structures of sjögrenite and pyroaurite, two stacking modifications of approximate composition Mg6Fe2(OH)16(CO3).4H2O, have been determined by X-ray diffraction using three-dimensional methods. Sjögrenite is hexagonal, with a 3·13, c 15·66 Å, space group P63/mmc , Z = ¼; pyroaurite is rhombohedral, with aH 3·13, cH 23·49 Å, space group R3̄m or R3m, Z = ⅜. Both structures are based on brucite-like layers, with magnesium and iron distributed among the octahedral positions. The cations appear to be largely disordered, although ordered regions may occur in some crystals. Between the brucite-like layers are the water molecules and carbonate groups. These are statistically arranged, with their oxygen atoms distributed among a larger number of possible sites.

The X-ray structure of a sodium peroxide hydrate, Na2O2•8H2O, and its reactions with carbon dioxide: relevance to the brightening of mechanical pulps

1997 ◽  
Vol 75 (1) ◽  
pp. 46-51 ◽  
Author(s):  
Geoffrey S. Hill ◽  
David G. Holah ◽  
Stephen D. Kinrade ◽  
Todd A. Sloan ◽  
Vincent R. Magnuson ◽  
...  
Keyword(s):  
Water Molecules ◽  
Monoclinic Space Group ◽  
Sodium Peroxide ◽  
X Ray Diffraction ◽  
X Ray ◽  
Mechanical Pulps ◽  
Main Component ◽  
Key Words Sodium ◽  
Centrosymmetric Structure ◽  
Oxygen Atoms

The main component of the solid originally believed to be a peroxosilicate with pulp-brightening properties has been shown to be Na2O2•8H2O. The solid crystallizes in the monoclinic space group C2/c, with an empirical formula H8O5Na, and with a = 14.335(3), b = 6.461(1), c = 11.432(2) Å, β = 118.28(3)°, and Z = 8. The centrosymmetric structure consists of a peroxide anion with an O—O distance of 1.499(2) Å. Each of these oxygen atoms is at the apex of an approximate square-based pyramid, the base of which consists of four oxygen atoms of water molecules. The bases of the two pyramids are staggered when viewed down the peroxide bond. Each sodium is at the centre of an approximate octahedron of water molecules, four of which bridge other sodium atoms and two bridge to the peroxide anions. One hydrogen atom of each of these two water molecules is terminal and the other two are hydrogen bonded to peroxide oxygen atoms. The compound reacts very rapidly with CO2 in moist air to form Na2CO3, but in drier conditions, formation of the carbonate can take many days and proceeds via a percarbonate, believed to be Na2CO4. This has been identified by infrared spectroscopy and X-ray powder diffraction and can persist for long periods in dry air. Key words: sodium peroxide hydrate, sodium percarbonate, pulp brightening, X-ray diffraction, infrared.

scholarly journals Synthesis, Structural Characterization, and Antibacterial Activity of Novel Erbium(III) Complex Containing Antimony

2018 ◽  
Vol 2018 ◽  
pp. 1-9
Author(s):  
Ting Liu ◽  
Rong-Gui Yang ◽  
Guo-Qing Zhong
Keyword(s):  
Ethylenediaminetetraacetic Acid ◽  
Antimicrobial Activities ◽  
Diffusion Method ◽  
Water Molecules ◽  
Equatorial Position ◽  
X Ray Diffraction ◽  
Monoclinic System ◽  
Adjacent Layer ◽  
X Ray ◽  
Oxygen Atoms

The novel 3D edta-linked heterometallic complex [Sb2Er(edta)2(H2O)4]NO3·4H2O (H4edta = ethylenediaminetetraacetic acid) was synthesized and characterized by elemental analyses, single-crystal X-ray diffraction, powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and thermal analysis. The complex crystallizes in the monoclinic system with space group Pm. In the complex, each erbium(III) ion is connected with antimony(III) ions bridging by four carboxylic oxygen atoms, and in each [Sb(edta)]− anion, the antimony(III) ion is hexacoordinated by two nitrogen atoms and four oxygen atoms from the edta4− ions, together with a lone electron pair at the equatorial position. The erbium(III) ion is octacoordinated by four oxygen atoms from four different edta4− ions and four oxygen atoms from the coordinated water molecules. The carboxylate bridges between antimony and erbium atoms form a planar array, parallel to the (1 0 0) plane. There is an obvious weak interaction between antimony atom and oxygen atom of the carboxyl group from the adjacent layer. The degradation of the complex proceeds in several steps and the water molecules and ligands are successively emitted, and the residues of the thermal decomposition are antimonous oxide and erbium(III) oxide. The complex was evaluated for its antimicrobial activities by agar diffusion method, and it has good activities against the test bacterial organisms.

scholarly journals Synthesis and Structural Characterization of the Tetranuclear Iron(Iii) Cluster with Salicylic Acid

2020 ◽  
Vol 15 (2) ◽  
pp. 62-68
Author(s):  
Viorina Gorinchoy
Keyword(s):  
Salicylic Acid ◽  
Diffraction Analysis ◽  
Structural Characterization ◽  
Spectroscopic Method ◽  
Water Molecules ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ir Spectroscopic ◽  
Oxygen Atoms

A new tetra-homonuclear iron(III) cluster, [Fe4O2(Sal)4(H2O)6]·4DMA·0.75H2O, where Sal= salicylic acid and DMA= N,N-dimethylacetamide consolidated via two µ3-oxo- and four salicylate-bridges was synthesized and characterized by IR spectroscopic method as well as by single crystal X-ray diffraction analysis. The structure of the obtained tetranuclear compound consists of four FeIII atoms in a “butterfly” arrangement. The coordination sphere of each of the two central FeIII atoms is generated by two μ3-oxo-bridging atoms and four oxygen atoms provided by the tridentate-bridging Sal2- ligands, while the coordination polyhedron of another two iron atoms involve six oxygen atoms from three water molecules, two salicylic and one μ3-oxigen atom. The Fe-O distances within Fe-O-Fe bridge are of 2.102(3) Å (for wing-body) and 2.038(3) Å (for body-body).

A Comparative X-Ray Diffraction Study of Aqueous MnSO4 and Crystals of MnSO4·5H2O

1982 ◽  
Vol 37 (6) ◽  
pp. 581-586 ◽  
Author(s):  
R. Caminiti ◽  
G. Marongiu ◽  
G. Paschina
Keyword(s):  
Crystal Structure ◽  
Experimental Data ◽  
Single Crystal ◽  
Diffraction Study ◽  
Water Molecules ◽  
X Ray Diffraction ◽  
X Ray ◽  
X Ray Scattering ◽  
Good Agreement ◽  
Single Crystal Analysis

Abstract X-ray single crystal analysis of MnSO4·5H2O shows that the manganese atoms are octahedrally coordinated by oxygen atoms, four of which belong to water molecules and two to sulphate groups. A model derived from the crystal structure was fitted to the X-ray scattering intensities from aqueous MnSO4. Good agreement with experimental data is achieved using a model in which Mn(H2O)6-z(OSO3)z+2-2z interacts with about ten water molecules and each sulphate ion with about seven water molecules.

X-Ray Diffraction Study of a Concentrated Al(NO3 )3 Solution

1980 ◽  
Vol 35 (12) ◽  
pp. 1368-1372 ◽  
Author(s):  
R. Caminiti ◽  
T. Radnai
Keyword(s):  
Experimental Data ◽  
Aqueous Solution ◽  
Hydrogen Bonds ◽  
Nearest Neighbors ◽  
Water Molecules ◽  
X Rays ◽  
X Ray Diffraction ◽  
X Ray ◽  
Weak Hydrogen Bonds ◽  
Good Agreement

Abstract The scattering of X-rays from a concentrated Al (NO3)3 aqueous solution has been measured and analyzed at 25 °C. Good agreement with experimental data is achieved through a model in which Al3+(H2O)6 interacts with twelve water molecules through short and linear H-bonds. The water molecules which are the nearest neighbors to the Al3+ ions have trigonal orientation and each 0 atom in the nitrate ion gives rise to about 2 weak hydrogen bonds with water molecules.

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