The structure of concentrated aqueous ammonium nitrate solutions

Walker, Paul Andreas; Lawrence, D. G.; Neilson, G. W.; Cooper, J. E.

doi:10.1039/f19898501365

Cited by 25 publications

(20 citation statements)

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“…and K+ have similar charge density characteristics, as shown by their viscosity B coefficients (Table 2). Neutron diffraction (Walker et al, 1989;Adya and Neilson, 1991), NMR (Perrin and Gipe, 1987), and Monte Carlo techniques all indicate that NH+ is weakly hydrated. Thus the weakly hydrated CFshould readily form inner sphere ion pairs with nitrogen-based protein cationic side chains, as neutron diffraction studies show that it does with cationic polyethylene imine (Bieze et al, 1994).…”

Section: Charge Neutralization On Proteinsmentioning

confidence: 99%

“…5. The nitrogen-based cations are judged to be chaotropes on the basis of the chromatographic behavior of the guanidinium ion on Sephadex G-1O (Washabaugh and Collins, 1986), and the following evidence that NH+ is weakly hydrated: a negative Jones-Dole viscosity B coefficient (Table 3); neutron diffraction studies (Adya and Neilson, 1991;Walker et al, 1989), NMR studies (Perrin and Gipe, 1987), and Monte Carlo simulations (Noto et al, 1991).…”

Section: Relationship Between the Hofmeister Series And Ionic Strengthmentioning

confidence: 99%

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Charge density-dependent strength of hydration and biological structure

Collins¹

1997

Biophysical Journal

1,145

1,216

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Small ions of high charge density (kosmotropes) bind water molecules strongly, whereas large monovalent ions of low charge density (chaotropes) bind water molecules weakly relative to the strength of water-water interactions in bulk solution. The standard heat of solution of a crystalline alkali halide is shown here to be negative (exothermic) only when one ion is a kosmotrope and the ion of opposite charge is a chaotrope; this standard heat of solution is known to become proportionally more positive as the difference between the absolute heats of hydration of the corresponding gaseous anion and cation decreases. This suggests that inner sphere ion pairs are preferentially formed between oppositely charged ions with matching absolute enthalpies of hydration, and that biological organization arises from the noncovalent association of moieties with matching absolute free energies of solution, except where free energy is expended to keep them apart. The major intracellular anions (phosphates and carboxylates) are kosmotropes, whereas the major intracellular monovalent cations (K+; arg, his, and lys side chains) are chaotropes; together they form highly soluble, solvent-separated ion pairs that keep the contents of the cell in solution.

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Section: Charge Neutralization On Proteinsmentioning

confidence: 99%

Section: Relationship Between the Hofmeister Series And Ionic Strengthmentioning

confidence: 99%

Charge density-dependent strength of hydration and biological structure

Collins¹

1997

Biophysical Journal

1,145

1,216

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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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confidence: 99%

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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“…*Interesting structural information was obtained in [ 22 ] for concentrated (12m and 18m) ammonium nitrate solutions. In particular, it was concluded that contact ion pairs are formed in the 18m solution.…”

mentioning

confidence: 99%

“…In particular, it was concluded that contact ion pairs are formed in the 18m solution. The authors [ 22 ] emphasize the system's complexity (see also the references in [ 22 ]). Note.…”

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confidence: 99%

Bulk properties and hydration numbers of ammonium nitrate and ammonium chloride in solution: A structural and thermodynamic analysis

Королев

2014

J Struct Chem

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The apparent volumes of the salts in the systems H 2 O-NH 4 Cl (298 K) and H 2 O-NH 4 NO 3 (273 K, 298 K, and 323 K) are reproduced with an accuracy of 0.03-0.01 cm 3 /mol by the equationwhere w 2 is the salt content (mass fractions). The study shows that there is a correspondence between the critical (for determining the hydration number) structural parameters-the intrinsic volume of the electrolyte and the volume of water in ion hydration shells-and the limiting (at w 2 = 1) partial molar volumes of the components. The hydration numbers at infinite dilution are 6.9 for NH 4 Cl at 298 K and 9.1, 6.7, and 6.4 for NH 4 NO 3 at 273 K, 298 K, and 323 K. The water volume in ion hydration shells decreases in the sequence: 3 NO , − Cl -, and 4 NH . + The hydration numbers decrease with increasing salt concentration. The study shows that within a simpler model φ = φ 0 + a 0.5 2 w , the hydration numbers are temperature independent. Ammonium salts play a special role in solution chemistry. Thus, the equality of characteristics of the 4 NH + and Clions was used as a basis to derive the standard partial volumes* [1] and heat capacities [2] of the separate ions in aqueous solution. A reference scale for the contribution of the separate ions in the chemical shift of water protons was suggested from the condition δ 0 ( 4 NH + ) = 0 [3]. According to the classification [4], the ammonium ion is a weak water structure breaker; however, it can be inferred from the data in [5] that it is rather a structure maker. Speaking about Cland 3 NO − , the classification [4] tells us that both anions are water structure breakers of approximately the same strength.Ammonium chloride and ammonium nitrate are important for atmospheric chemistry [6,7]. The solubility of NH 4 Cl and NH 4 NO 3 in water at 298 K is 28.4% (7.4m) and 68.2% (26.8m), respectively (m is molality). At the same time the concentration of NH 4 Cl in small aerosol drops can be as high as 60% (28m) [7]. Ammonium nitrate can exist under similar conditions in the form of a virtually anhydrous melt [7]. *The standard partial molar volume of NH 4 Cl in aqueous solution at 298 K is equal to two molar volumes of water at this temperature.

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The structure of concentrated aqueous ammonium nitrate solutions

Cited by 25 publications

References 1 publication

Charge density-dependent strength of hydration and biological structure

Charge density-dependent strength of hydration and biological structure

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

Bulk properties and hydration numbers of ammonium nitrate and ammonium chloride in solution: A structural and thermodynamic analysis

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