Determination of the number of inner-sphere water molecules in lanthanide(III) polyaminocarboxylate complexes

1992 ◽  
pp. 463 ◽  
Author(s):  
M. Carmen Alpoim ◽  
Ana M. Urbano ◽  
Carlos F. G. C. Geraldes ◽  
Joop A. Peters
Keyword(s):  
Water Molecules ◽  
Inner Sphere

Number of inner-sphere water molecules in Gd3+ and Eu3+ complexes of DTPA-amide and -ester conjugates

1988 ◽  
Vol 8 (2) ◽  
pp. 191-199 ◽  
Author(s):  
Carlos F. G. C. Geraldes ◽  
A. Dean Sherry ◽  
William P. Cacheris ◽  
Kah-Tiong Kuan ◽  
Rodney D. Brown ◽  
...  
Keyword(s):  
Water Molecules ◽  
Inner Sphere

Etude structurale par diffraction des RX et spectroscopie IR des hydrates 10 et 8.4 Å de kaolinite

1999 ◽  
Vol 32 (5) ◽  
pp. 968-976 ◽  
Author(s):  
S. Jemai ◽  
A. Ben Haj Amara ◽  
J. Ben Brahim ◽  
A. Plançon
Keyword(s):  
Water Molecule ◽  
Octahedral Site ◽  
Ammonium Fluoride ◽  
Water Molecules ◽  
X Ray Diffraction ◽  
Tetrahedral Sheet ◽  
X Ray ◽  
Octahedral Sites ◽  
Sheet Structure

Two hydrated kaolinites, characterized by 10 and 8.4 Å basal distances, were synthesized by treating the kaolinite KGa-1 with dimethyl sulfoxide (DMSO) and ammonium fluoride (NH4F). The X-ray diffraction study was based on a comparison between the experimental and calculated profiles. This study was conducted in two steps: firstly, the study of the 00lreflections enabled the determination of the stacking mode alongc*, the number of water molecules and their positions along the normal to the plane of the sheet structure; secondly, the study of thehkbands, withhand/ork≠ 0, enabled the determination of the stacking mode and the positions of the water molecules in the (a,b) plane. The 10 Å hydrated kaolinite is characterized by two water molecules per Al2Si2O5(OH)4unit, situated at 3 and 3.4 Å from the hydroxyl surface, over the octahedral sites. Two adjacent layers are translated with respect to each other, withT11= −0.38a− 0.37b+ 10n. The 8.4 Å hydrated kaolinite is characterized by one water molecule per Al2Si2O5(OH)4unit, situated at 2.4 Å from the hydroxyl surface and inserted between the vacant octahedral site and the ditrigonal cavity of the tetrahedral sheet. The corresponding interlayer shift isT11= −0.355a+ 0.35b+ 8.4n.

scholarly journals Gas Transfer of Metals during the Destruction of Efflorescent Sulfates from the Belovo Plant Sulfide Slag, Russia

Minerals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 344
Author(s):  
Svetlana Bortnikova ◽  
Natalya Abrosimova ◽  
Nataliya Yurkevich ◽  
Valentina Zvereva ◽  
Anna Devyatova ◽  
...  
Keyword(s):  
Major And Trace Elements ◽  
Water Molecules ◽  
Gas Transfer ◽  
Structural Water ◽  
Fermentation Products ◽  
X Ray ◽  
Gas Condensates ◽  
Gas Phase Transport ◽  
Phase Transport

This paper demonstrates the results of experiments for the determination of the composition of gases during the dehydration of sulfates (Na-jarosite, melanterite, and chalcanthite) collected at the surface of pyrometallurgical waste heaps. The volatilization of various elements, and vapor–gas phase transport from three sulfate groups were investigated by stepwise laboratory heating at 45, 55, and 65 °C. The sample of yellow efflorescence mainly consisted of Na-jarosite, the white efflorescence contained melanterite as the major mineral, and the blue efflorescence sample consisted of chalcanthite. These all contained a few impurities up to 5 %. The highest total dissolved solids (TDS) was found in the gas condensates from melanterite (59 mg/L), followed by chalcanthite (29 mg/L) and Na-jarosite (17 mg/L). It was determined that major and trace elements in the condensate can be trapped by water vapor and can migrate with the vapor phase during the desorption and dehydration of hydrous sulfates. X-ray diffractograms showed that Na-jarosite remained stable throughout the temperature range, whilst the separation of melanterite’s structural water occurred at 40 °C, and chalcanthite completely lost two water molecules at 50 °C. The gas condensates contained acetates and formates, which could be the fermentation products of bacterial communities. Some of the strains—Micrococcaceae sp., Bacillus sp., and Microbacteriaceae sp.—were cultivated.

scholarly journals High-resolution neutron and X-ray diffraction room-temperature studies of an H-FABP–oleic acid complex: study of the internal water cluster and ligand binding by a transferred multipolar electron-density distribution

IUCrJ ◽  
2016 ◽  
Vol 3 (2) ◽  
pp. 115-126 ◽  
Author(s):  
E. I. Howard ◽  
B. Guillot ◽  
M. P. Blakeley ◽  
M. Haertlein ◽  
M. Moulin ◽  
...  
Keyword(s):  
Oleic Acid ◽  
Fatty Acid ◽  
High Resolution ◽  
Density Distribution ◽  
Electron Density ◽  
Electron Density Distribution ◽  
Room Temperature ◽  
Water Molecules ◽  
X Ray

Crystal diffraction data of heart fatty acid binding protein (H-FABP) in complex with oleic acid were measured at room temperature with high-resolution X-ray and neutron protein crystallography (0.98 and 1.90 Å resolution, respectively). These data provided very detailed information about the cluster of water molecules and the bound oleic acid in the H-FABP large internal cavity. The jointly refined X-ray/neutron structure of H-FABP was complemented by a transferred multipolar electron-density distribution using the parameters of the ELMAMII library. The resulting electron density allowed a precise determination of the electrostatic potential in the fatty acid (FA) binding pocket. Bader's quantum theory of atoms in molecules was then used to study interactions involving the internal water molecules, the FA and the protein. This approach showed H...H contacts of the FA with highly conserved hydrophobic residues known to play a role in the stabilization of long-chain FAs in the binding cavity. The determination of water hydrogen (deuterium) positions allowed the analysis of the orientation and electrostatic properties of the water molecules in the very ordered cluster. As a result, a significant alignment of the permanent dipoles of the water molecules with the protein electrostatic field was observed. This can be related to the dielectric properties of hydration layers around proteins, where the shielding of electrostatic interactions depends directly on the rotational degrees of freedom of the water molecules in the interface.

The mobility of alkali ions in gases III. The mobility of alkali ions in water vapour

1939 ◽  
Vol 172 (948) ◽  
pp. 51-54 ◽  
Keyword(s):  
Water Vapour ◽  
Infinite Dilution ◽  
Pure Water ◽  
Atomic Weight ◽  
Alkali Atom ◽  
Water Molecules ◽  
Degree Of Hydration ◽  
Alkali Ions ◽  
Alkali Ion

It is known that in electrolytes at infinite dilution the mobility of an alkali ion increases with its mass and this has been attributed by some to a decrease in its degree of hydration as the size of the alkali atom increases. In Part I evidence was obtained, at least in helium and neon, that the average number of water molecules which are attached to an alkali ion when water is present as an impurity also decreases as the atomic weight of the ion increases. As a natural corollary to this work a determination of the mobility of the alkali ions in pure water vapour has been undertaken and is here described. The method and apparatus of Part I was used. The nature of the ion from the source was first verified by running it in a pure gas which was then pumped off and water vapour introduced. The results are shown in fig. 1, where the mobility of the ion is plotted with E/p . For the sake of clearness the results for Rb + are excluded from the graph except at low values of E/p . The remainder of the Rb + graph follows more or less that for Na + .

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