Hydration of the bromine ion in a supercritical 1:1 aqueous electrolyte

Ferlat, G.; San-Miguel, Alfonso; Jal, J. F.; Soetens, Jean-Christophe; Bopp, P.; Daniel, Isabelle; Guillot, Stéphane; Hazemann, Jean Louis; Argoud, R.

doi:10.1103/physrevb.63.134202

Cited by 49 publications

(41 citation statements)

References 54 publications

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“…All the spectra exhibit a constant absorption edge at E 0 = 13,478 ± 0.5 eV with a relatively broad white line with a maximum at 13,482 ± 1.5 eV. The XANES spectrum of the parent glass is similar to those previously published for alkali bromide aqueous solutions (Ferlat et al, 2001;Evans et al, 2009;Louvel, 2011). Changes in the shape of the XANES spectra are observed between the parent glass, the melts and the glasses quenched from high pressure, which suggests substantial differences in the local structure of Br at different P-T conditions.…”

Section: High-pressure Glasses and Meltsmentioning

confidence: 62%

“…Following Louvel (2011), the fitting model combined the structure of a hydration shell [Br(H 2 O)n] and the structure from crystalline NaBr, with the Na-Br distance determined from the reference analyses. The hydration shell was modeled by considering that Br is coordinated by 6 water molecules [Br(H 2 O) 6 ] − with a mean Br-O distance of 3.40 Å (Ferlat et al, 2001;D'Angelo et al, 2010). The EXAFS spectrum of the parent glass at ambient pressure is accurately modeled with a first hydration shell with 3.5 ± 0.7 water molecules (N Br-O (-H) ) at a mean Br-O (oxygen of solvating H2O molecules) distance of 3.36 ± 0.09 Å (Table 3) and a Br-Na shell with a coordination of 2.5 ± 1 and a mean Br-Na distance of 2.91 ± 0.37 Å.…”

Section: High-pressure Glasses and Meltsmentioning

confidence: 99%

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Bromine speciation in hydrous silicate melts at high pressure

et al. 2015

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International audienceBr speciation in hydrous silicate melts at high pressure has been investigated up to 7.6 GPa using X-ray Absorption Spectroscopy (XAS) at the Br K-edge in a Paris-Edinburgh press. Br in silicate melts is surrounded by an average of 6 Na cations, a number slightly increasing with pressure (5.8 to 6.6), with a Br-Na distance increasing from 3.49 to 3.72 Å. Two oxygens, either from a water, an –OH molecule or from the tetrahedral silicate network, with an average Br-O distance of 1.80 Å, form the closest coordination shell around Br ions. The persistence of an alkali shell around Br, in a structure similar to crystalline NaBr, throughout the pressure range investigated shows that Br can be retained in the melt structure at relatively high pressure and supports the idea of its deep recycling. Finally, our results confirm that Br could be efficiently degassed with water at low pressures and that Br may also have been efficiently degassed along with water during the early stages of an oxidized magma ocean

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Section: High-pressure Glasses and Meltsmentioning

confidence: 62%

Section: High-pressure Glasses and Meltsmentioning

confidence: 99%

Bromine speciation in hydrous silicate melts at high pressure

et al. 2015

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“…For this reason a number of studies have focussed on RbBr (e.g. Fulton et al, 1996;Newville et al, 1997;Wallen et al, 1997;Ferlat et al, 2001Ferlat et al, , 2002 because the absorption edges of Rb and Br are at sufficiently high energy (13-16 keV), that the Xrays of interest pass through experimental apparatus without excessive absorption. RbBr is similar to NaCl in that it is a cubic ionic compound of group I and group VII ions.…”

Section: Introductionmentioning

confidence: 99%

The effect of CO2 on the speciation of RbBr in solution at temperatures to 579°C and pressures to 0.26GPa

Evans

Gordon

Mavrogenes

et al. 2009

Geochimica et Cosmochimica Acta

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“…Nevertheless, some fundamental studies based on an extended X-ray absorption fine structure (EXAFS) spectroscopy have been applied to investigate the detailed solvation structure of ionic solution [11][12][13][14][15][16][17][18][19] and ions adsorbed in clay. EXAFS analyses require a structural model around an adsorbed ion in order to determine the site where ions are adsorbed on the clay surface.…”

Section: Introductionmentioning

confidence: 99%

A combined X-ray absorption spectroscopy and molecular dynamic simulation to study the local structure potassium ion in hydrated montmorillonite

2015

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Atomistic local structure of potassium ion adsorbed in hydrated montmorillonite (MMT) was investigated based on a combination of an extended X-ray absorption fine structure (EXAFS) spectroscopy and classical molecular dynamics (MD) simulation. The accuracy of the representative MMT atomistic model with PCFF-INTERFACE force field was validated. MD-simulated EXAFS spectra were calculated from trajectories of hydrated MMT atomic coordinates and the results were in satisfactory agreement with corresponding experimental EXAFS spectra. Interlayer spacing determined by X-ray diffraction was consistent with the mono-layer hydrated MMT structure. The first coordination shell of K ? ion in monohydrated MMT was formed by 5 water oxygen atoms at an average K-O W distance of 2.85 Å and the second coordination shell of 6 oxygen atoms from both sides of the closest silicate tetrahedral sheet at K-O MMT = 3.41 Å . For hydrated K ? -MMT, MD and EXAFS results confirm that K ? counter ions form the inner-sphere surface complex and that the adsorbed sites were located with the vicinity edge of a basal oxygen hexagonal cavity in the silicate tetrahedral sheets of MMT. For higher-layer hydrated MMT, K ? ions can form surface complexes that are inner-sphere, outersphere, and transient diffuse-layer species depending on the number of intercalated water in the clay. Water molecules are of less ordered arrangement in the monohydrated MMT due to the confinement effect from the clay surface. K ? counter ions in the single layer hydrates are almost trapped within the cavities of the basal planes surface.

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Hydration of the bromine ion in a supercritical 1:1 aqueous electrolyte

Cited by 49 publications

References 54 publications

Bromine speciation in hydrous silicate melts at high pressure

Bromine speciation in hydrous silicate melts at high pressure

The effect of CO2 on the speciation of RbBr in solution at temperatures to 579°C and pressures to 0.26GPa

A combined X-ray absorption spectroscopy and molecular dynamic simulation to study the local structure potassium ion in hydrated montmorillonite

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