X-ray Diffraction Study of Aqueous Solutions of ZnSO<sub>4</sub>

Licheri, G.; Paschina, G.; Piccaluga, G.; Pinna, G.

doi:10.1515/zna-1982-1012

Cited by 21 publications

(23 citation statements)

References 10 publications

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“…2 , was found in 0.6-3.1 M aqueous solutions of ZnSO 4 [16]. In addition, the expected regular octahedral coordination of zinc ions [7,10] simplifies the EXAFS analysis allowing us to concentrate on the high-frequency contribution mentioned before.…”

Section: Introductionmentioning

confidence: 91%

“…The presence of a second hydration shell around some ions in aqueous solutions has been previously studied and confirmed by x-ray diffraction (XRD) [7,10]. Among the series of 3d elements, zinc is a promising candidate for such a study because its second hydration shell in water is well established by XRD [16][17][18][19] and was also observed by Monte Carlo simulations [20]. A well ordered second shell, consisting of ∼8-13 water molecules located around the Zn 2+ ions at a mean distance R(Zn-OH 2 ) =4.…”

Section: Introductionmentioning

confidence: 95%

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X-ray absorption spectroscopy and molecular dynamics studies of hydration in aqueous solutions

Kuzmin¹,

Obst²,

Purans³

1997

J. Phys.: Condens. Matter

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The hydration of Zn 2+ ions in aqueous solutions was studied at room temperature by x-ray absorption spectroscopy and molecular dynamics (MD) simulation. The extended x-ray absorption fine structure (EXAFS) above the Zn K-edge was interpreted using the multiplescattering approach by taking into account only one coordination shell composed of 6 ± 0.2 water molecules at R(Zn-O) = 2.06± 0.02Å with a mean square relative displacement (MSRD) σ 2 = 0.009 ± 0.002Å 2. No evidence of significant contributions from the second hydration shell to the EXAFS signal was found in the solutions. This is explained by the cancellation interference effect between double-scattering and single-scattering EXAFS signals in the second shell due to large thermal/static disorder (σ 2 ∼ 0.1Å 2) as predicted by our MD simulation and by known results of diffraction techniques.

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Section: Introductionmentioning

confidence: 91%

Section: Introductionmentioning

confidence: 95%

X-ray absorption spectroscopy and molecular dynamics studies of hydration in aqueous solutions

Kuzmin¹,

Obst²,

Purans³

1997

J. Phys.: Condens. Matter

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“…The I obs (2θ) were corrected for a background, an absorption, a polarization by the conventional methods [32], and normalized by a high angle and Krough-MoeNorman methods [33,34]. Incoherent scatterings multiplied by a Breit-Dirac recoil factor were subtracted to yield observed scattering intensity I coh (s).…”

Section: Laxs Measurementmentioning

confidence: 99%

Liquid Structure and the Ion-Ion Interactions of Ethylammonium Nitrate Ionic Liquid Studied by Large Angle X-Ray Scattering and Molecular Dynamics Simulations

Umebayashi

Chung

Mitsugi

et al. 2008

J. Comput. Chem. Jpn.

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Room temperature ionic liquids (RTILs) are useful as new solvents or materials owing to their favorable properties such as negligible vapor pressure, non-flammability, and wide electrochemical window. For further development of new RTILs, it is indispensable to understand macroscopic properties as solvent and/or liquids of RTILs at a molecular or atomistic level. Here, liquid structure and the ion-ion interactions of room temperature ionic liquid ethylammonium nitrate (EAN) were studied by means of large angle X-ray scattering (LAXS) experiment and molecular dynamics simulations. X-ray interference function for EAN shows a small peak of 0.62Å -1 indicating nano-scale segregation in the ionic liquid. X-ray radial distribution function as the form of D(r) -4πr 2 ρ 0 evidently shows a peak of 3.4 and broad ones of 4.7, 8 and 12Å, suggesting that EAN has long range ordering in the liquid state. The intra-molecular X-ray interference function was estimated on the basis of molecular geometries found in crystals to yield the inter-molecular X-ray pair correlation function G LAXS inter (r). In G LAXS inter (r), peaks of 3.0, 3.4, and 4.7Å were found as the atom-atom correlation. The peak of 3.0Å can be assigned to the atom-atom correlation of N (C 2 H 5 NH 3 + ) O (NO 3 -) in the NH O hydrogen bonding. In addition, the peak of 3.4Å is also ascribable to C (C 2 H 5 NH 3 + ) O (NO 3 -) correlations in the CH O interactions. Molecular dynamics simulations based on newly developed force fields to describe a series of primary ammonium cation were performed to ascribe the peaks found in G LAXS inter (r). The X-ray interference function i MD (s) and the pair correlation function G MD (r) derived from simulations were reasonably in agreement with the experimental ones. According to the partial atom-atom correlation functions derived from the simulations, the experimentally observed peaks of 3.0 and 3.4Å can be ascribable to the NH O and the CH O correlations in the closest ethylammonium and nitrate interaction, respectively. The CH O interactions may play an important role in macroscopic properties of this kind of ionic liquids.

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“…In water, experimental studies point to an average coordination number of 6 at room temperature, with a first solvation shell made of H 2 O molecules only. [1][2][3][4][5][6][7][8][9][10][11] In comparison, early theoretical studies of the aqueous environment of Zn based on molecular clusters, 3,[12][13][14][15][16] lead to contrasted results, depending on their theoretical level (e.g. MP2 vs. hybrid- DFT) and numerical parameters (e.g.…”

Section: Introductionmentioning

confidence: 99%

van der Waals Contribution to the Relative Stability of Aqueous Zn(2+) Coordination States

Ducher

Pietrucci

Balan

et al. 2017

J. Chem. Theory Comput.

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Many properties of aqueous cations depend on their coordination state. However, the lack of long-range order and the dynamic character of aqueous solutions make it difficult to obtain information beyond average coordination parameters. A thorough understanding of the molecular-scale environment of aqueous cations usually requires a combination of experimental and theoretical approaches. In the case of Zn, significant discrepancies occur among theoretical investigations based on first-principles molecular dynamics (FPMD) or free-energy calculations, although experimental data consistently point to a dominant hexaaquo-zinc complex (Zn[HO]) in pure water. In the present study, the aqueous speciation of zinc is theoretically investigated by combining FPMD simulations and free-energy calculations based on metadynamics and umbrella-sampling strategies. The simulations are carried out within the density functional theory (DFT) framework using for the exchange-correlation functional either a standard generalized gradient approximation (GGA) or a nonlocal functional (vdw-DF2) which includes van der Waals interactions. The theoretical environment of Zn is confronted to experiment by comparing calculated and measured X-ray absorption spectra. It is shown that the inclusion of van der Waals interactions is crucial for the correct modeling of zinc aqueous speciation, whereas GGA incorrectly favors tetraaquo- (Zn[HO]) and pentaaquo-zinc (Zn[HO]) complexes, results obtained with the vdW-DF2 functional show that the hexaaquo-zinc complex is more stable than the tetraaquo and pentaaquo-zinc complexes by 13 and by 4 kJ mol, respectively. These results highlight the critical importance of even subtle interactions for the correct balance of different coordination states in aqueous solutions. However, for a given coordination state, GGA leads to a reasonable description of the geometry of the aqueous complex.

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X-ray Diffraction Study of Aqueous Solutions of ZnSO₄

Cited by 21 publications

References 10 publications

X-ray absorption spectroscopy and molecular dynamics studies of hydration in aqueous solutions

X-ray absorption spectroscopy and molecular dynamics studies of hydration in aqueous solutions

Liquid Structure and the Ion-Ion Interactions of Ethylammonium Nitrate Ionic Liquid Studied by Large Angle X-Ray Scattering and Molecular Dynamics Simulations

van der Waals Contribution to the Relative Stability of Aqueous Zn(2+) Coordination States

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X-ray Diffraction Study of Aqueous Solutions of ZnSO4

Cited by 21 publications

References 10 publications

X-ray absorption spectroscopy and molecular dynamics studies of hydration in aqueous solutions

X-ray absorption spectroscopy and molecular dynamics studies of hydration in aqueous solutions

Liquid Structure and the Ion-Ion Interactions of Ethylammonium Nitrate Ionic Liquid Studied by Large Angle X-Ray Scattering and Molecular Dynamics Simulations

van der Waals Contribution to the Relative Stability of Aqueous Zn(2+) Coordination States

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X-ray Diffraction Study of Aqueous Solutions of ZnSO₄