Water exchange on magnesium(II) in aqueous solution: a variable temperature and pressure17O NMR study

Bleuzen, Anne; Pittet, Pierre-André; Helm, Lothar; Merbach, André E.

doi:10.1002/(sici)1097-458x(199711)35:11<765::aid-omr169>3.0.co;2-f

Cited by 131 publications

(196 citation statements)

References 7 publications

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“…The NMR lineshape for an exchanging two-site system can be calculated from the modified Bloch equations (see Bleuzen et al, 1997), given in matrix form:…”

Section: Rate Equationssupporting

confidence: 55%

Residence times for protons bound to three oxygen sites in the AlO4Al12(OH)24(H2O)127+ polyoxocation

Houston

Phillips

Casey

2006

Geochimica et Cosmochimica Acta

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“…The NMR lineshape for an exchanging two-site system can be calculated from the modified Bloch equations (see Bleuzen et al, 1997), given in matrix form:…”

Section: Rate Equationssupporting

confidence: 55%

Residence times for protons bound to three oxygen sites in the AlO4Al12(OH)24(H2O)127+ polyoxocation

Houston

Phillips

Casey

2006

Geochimica et Cosmochimica Acta

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“…The water exchange rate around aqueous Cd 2+ is faster than 10 8 s −1 (Eigen, 1963;Inada et al, 2005) whereas that around Co 2+ is 3.2 × 10 6 s − 1 (Ducommun et al, 1980). For comparison, the exchange rate around Mg 2+ is 6.7 × 10 5 s − 1 and 5.3 × 10 5 s − 1 according to Bleuzen et al (1997) and Neely and Connick (1970), respectively, and Mg is known to easily form hydrates at room temperature. In contrast, the water exchange rate around Ca 2+ is higher than 10 10 s −1 (Kerisit and Parker, 2004).…”

Section: Origin Of the Differences Between Heterogeneous Growth Of Camentioning

confidence: 99%

Heterogeneous growth of cadmium and cobalt carbonate phases at the 101¯4 calcite surface

Ilton

Engelhard

et al. 2015

Chemical Geology

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The ability of surface precipitates to form heteroepitaxially is an important factor that controls the extent of heterogeneous growth. In this work, the growth of cadmium and cobalt carbonate phases on 1014 calcite surfaces is compared for a range of initial saturation states with respect to otavite (CdCO 3 ) and sphaerocobaltite (CoCO 3 ), two isostructural metal carbonates that exhibit different lattice misfits with respect to calcite (−4% and −15%, respectively, based on 1014 surface areas). Calcite single crystals were reacted in static conditions for 16 h with CdCl 2 and CoCl 2 aqueous solutions with initial concentrations 0.3 ≤ [Cd 2+ ] 0 ≤ 100 μM and 25 ≤ [Co 2+ ] 0 ≤ 200 μM. The reacted crystals were imaged in situ with atomic force microscopy (AFM) and analyzed ex situ with X-ray photoelectron spectroscopy (XPS). AFM images of Cd-reacted crystals showed the formation of large islands elongated along the 421 h i direction, clear evidence of heteroepitaxial growth, whereas surface precipitates on Co-reacted crystals were small round islands. Deformation of calcite etch pits in both cases indicated the incorporation of Cd and Co at step edges. XPS analysis pointed to the formation of a Cd-rich (Ca,Cd)CO 3 solid solution coating atop the calcite substrate. In contrast, XPS measurements of the Co-reacted crystals provided evidence for the formation of a mixed hydroxy-carbonate cobalt phase despite supersaturation with respect to CoCO 3 . The combined AFM and XPS results suggest that the lattice misfit between CoCO 3 and CaCO 3 is too large to allow for heteroepitaxial growth of a pure cobalt carbonate phase on calcite surfaces in aqueous solutions and at ambient conditions. The use of the satellite structure of the Co 2p 3/2 photoelectron line as a tool for determining the nature of cobalt surface precipitates is also discussed.

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“…We emphasize that the 2 ns MD simulations are not intended to capture the entire water dissociation process which is very around Mg 2+ ($6.7 Â 10 5 s À1 ), corresponding to an order of magnitude of 1 exchange event per microsecond (Bleuzen et al, 1997). The MD simulation is only used to generate local water structure around Mg 2+ .…”

Section: Molecular Dynamics Simulations Of Mg 2+ and Mg 2+ With Hs àmentioning

confidence: 99%

“…We use a combination of computational methods ranging from classical molecular dynamics (MD) simulations to ab initio quantum mechanical calculations with model clusters. Alternative solution-phase mechanisms are the associative mechanism where a ligand such as CO 2À 3 binds with a hexa-coordinated metal center to form a hepta-coordinated intermediate (Eigen and Wilkins, 1965), and the concerted or interchange mechanism where water leaves and CO 2À 3 associates simultaneously with the Mg 2+ center (e.g., Bleuzen et al, 1997). The promoting effect of HS À may also involve a heterogeneous mechanism at the interface of a solid precursor phase.…”

Section: Introductionmentioning

confidence: 99%

A computational study of Mg2+ dehydration in aqueous solution in the presence of HS− and other monovalent anions – Insights to dolomite formation

Yang

Sahai

Romanek

et al. 2012

Geochimica et Cosmochimica Acta

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Water exchange on magnesium(II) in aqueous solution: a variable temperature and pressure17O NMR study

Cited by 131 publications

References 7 publications

Residence times for protons bound to three oxygen sites in the AlO4Al12(OH)24(H2O)127+ polyoxocation

Residence times for protons bound to three oxygen sites in the AlO4Al12(OH)24(H2O)127+ polyoxocation

Heterogeneous growth of cadmium and cobalt carbonate phases at the 101¯4 calcite surface

A computational study of Mg2+ dehydration in aqueous solution in the presence of HS− and other monovalent anions – Insights to dolomite formation

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