Intermediate range order in concentrated aqueous solutions of copper nitrate. X-ray diffraction and Raman investigations

Marques, M. Alves; Marques, Miguel; Cabaço, M. Isabel; Gaspar, Augusta; Almeida, M.L. de

doi:10.1016/j.molliq.2003.08.014

Cited by 14 publications

(14 citation statements)

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“…The existence of an intermediate range order is considered as very plausible for aqueous solutions of chromium nitrate and for solutions of cerium chloride in the concentration ranges 1.0-2.5 mol dm − 3 and 1-3 mol dm − 3 respectively. The approximate assignment of quasi symmetrical models similar to those used for many solutions analyzed and reported in previous articles [1][2][3][4][5][6][7][8][9][10][11][12][13] seems to be acceptable to interpret the X-ray diffraction experiments obtained from concentrated aqueous solutions of cerium chloride. Moreover for cerium chloride solutions Raman experiments are compatible with the obtained ones by X-ray diffraction.…”

Section: Resultsmentioning

confidence: 78%

“…Some authors of this contribution have paid a continued attention to concentrated aqueous solutions of salts of metallic cations. When the salts are constituted by ions of different valences X-ray diffraction investigations demonstrate that an intermediate range order should exist in these solutions [1][2][3][4][5][6][7][8][9][10][11][12][13]. If the constituent ions are both monovalent, as for instance sodium chloride, or both divalent, as the magnesium or the zinc sulphate, no trace of an intermediate order was detected in the diffraction patterns.…”

Section: Introductionmentioning

confidence: 99%

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The structure of concentrated aqueous solutions of chromium nitrate and cerium chloride studied by X-ray diffraction and Raman spectroscopy

Cabaço

Marques

Gaspar

et al. 2007

Journal of Molecular Liquids

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Concentrated aqueous solutions of chromium nitrate and cerium chloride were investigated by X-ray diffraction and Raman spectroscopy. The X-ray diffraction patterns of two sets of solutions (1.60 up to 2.48 mol dm − 3 for chromium nitrate and 0.98 up to 2.81 mol dm − 3 for cerium chloride) display an intense maximum, prepeak, in the angular region about Q 0 ∼ 0.9 Å − 1 (Q = 4 π sin θ / λ, θ being the diffracting angle). The value of Q 0 corresponding to these maxima is proportional to the power 1/3 of the molar concentration. The proportionality coefficient has the value that should be observed for a close packing (fcc network) if assumed for cations. This study demonstrates, once more, the existence of an intermediate range order (up to ∼10 Å) in very concentrated aqueous solutions of salts constituted by small ions of different valences, range order previously reported by these authors in many articles. Raman experiments are in consonance with X-ray diffraction results.

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Section: Resultsmentioning

confidence: 78%

Section: Introductionmentioning

confidence: 99%

The structure of concentrated aqueous solutions of chromium nitrate and cerium chloride studied by X-ray diffraction and Raman spectroscopy

Cabaço

Marques

Gaspar

et al. 2007

Journal of Molecular Liquids

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“…The mineral Likasite (Cu 3 NO 3 (OH) 5 .2H 2 O) has three distinct vibrating units namely NO 3 , OH and H 2 O each of which will have a characteristic vibrational spectrum. Such a mineral lends itself to Raman spectroscopy.…”

Section: Resultsmentioning

confidence: 99%

“…It is obvious that very few spectroscopic studies have been forthcoming on the types of minerals listed above. The use of Raman spectroscopy to study nitrates is embedded in the history of Raman spectroscopy [5][6][7][8][9][10]. In this work we apply Raman spectroscopy using a thermal stage to the study of a natural sample of likasite at 298 and 77 K.…”

Section: Introductionmentioning

confidence: 99%

Raman spectroscopy of likasite at 298 and 77K

Frost

Erickson

Weier

et al. 2005

Spectrochimica Acta Part A: Molecular and Biomolecular Spectros

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Copyright 2005 Elsevier AbstractRaman spectroscopy at 298 and 77 K has been used to study the structure of likasite, a naturally occurring basic copper(II)nitrate of formula Cu 3 NO 3 (OH) 5 .2H 2 O. An intense sharp band is observed at 3522 cm -1 at 298 K which splits into two bands at 3522 and 3505 cm -1 at 77 K and is assigned to the OH stretching mode. The two OH stretching bands at 3522 and 3505 provide estimates of the hydrogen bond distances of these units as 2.9315 and 2.9028 Å. The significance of this result is that equivalent OH units in the 298 K spectrum become two non-equivalent OH units at 77 K suggesting a structural change by cooling to liquid nitrogen temperature. A number of broad bands are observed in the 298 K spectrum at 3452, 3338, 3281 and 3040 cm -1 assigned to H 2 O stretching vibrations with estimates of the hydrogen bond distances of 2.8231, 2.7639, 2.7358 and 2.6436 Å. Three sharp bands are observed at 77 K at 1052, 1050 and 1048 cm -1 attributed to the ν 1 symmetric stretching mode of the NO 3 units. Only a single band at 1050 cm -1 is observed at 298 K, suggesting the nonequivalence of the NO 3 units at 77 K, confirming structural changes in likasite by cooling to 77 K.

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“…has been characterized as exhibiting mild interactions with water, i.e., weakly hydrated as a result of its small charge and relatively large effective ionic that induce limited distortion of the hydrogen bonding of the surrounding water [172][173] . These features might have contributed to the large disparity in the reported water coordination of the nitrate anion from different experimental sources, including NMR [174][175][176][177][178][179][180] , IR [181][182][183][184][185][186][187] , Raman [173][174][188][189][190][191][192][193][194][195][196][197] , XRD 172-173, 190, 193, 195-204 , as well as NDIS [205][206][207][208][209][210] , and point to unresolved concerns regarding the determination and interpretation of the hydration microstructure of nitrates in a variety of aqueous environments 63 .…”

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Toward the understanding of hydration phenomena in aqueous electrolytes from the interplay of theory, molecular simulation, and experiment

Chialvo

Vlček

2016

Fluid Phase Equilibria

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We study the microstructural analysis of aqueous electrolytes and present a detailed account of the fundamentals underlying the neutron scattering with isotopic substitution (NDIS) approach for the experimental determination of ion coordination numbers in systems involving both halide anions and oxyanions. We place particular emphasis on the frequently overlooked ion-pairing phenomenon, identify its microstructural signature in the neutron-weighted distribution functions, and suggest novel techniques to deal with either the estimation of the ion-pairing magnitude or the correction of its effects on the experimentally measured coordination numbers. We illustrate the underlying ideas by applying these new developments to the interpretation of four NDIS test-cases via molecular simulation, as convenient dry runs for the actual scattering experiments, for representative aqueous electrolyte solutions at ambient conditions involving metal halides and nitrates.

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Intermediate range order in concentrated aqueous solutions of copper nitrate. X-ray diffraction and Raman investigations

Cited by 14 publications

References 27 publications

The structure of concentrated aqueous solutions of chromium nitrate and cerium chloride studied by X-ray diffraction and Raman spectroscopy

The structure of concentrated aqueous solutions of chromium nitrate and cerium chloride studied by X-ray diffraction and Raman spectroscopy

Raman spectroscopy of likasite at 298 and 77K

Toward the understanding of hydration phenomena in aqueous electrolytes from the interplay of theory, molecular simulation, and experiment

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