Ca neighbors from XANES spectroscopy: A tool to investigate structure, redox, and nucleation processes in silicate glasses, melts, and crystals

Cicconi, Maria Rita; Ligny, Dominique de; Gallo, Tamires; Neuville, Daniel R.

doi:10.2138/am-2016-5663

Cited by 20 publications

(12 citation statements)

References 21 publications

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“…Unfortunately, the spectroscopy is unable to separate the two contributions, leading to an apparent up-shift (or down-shift in Mg-based glasses) of the frequency when cation oxide is replaced by aluminum oxide. This is however well correlated with the 23 Na NMR observed between sodium silicate and aluminosilicate glasses 30 where a NMR chemical shift is observed between charge compensator and network modifier cations, and also with XANES results at the Ca K-edge of CaO-SiO 2 and 25CaO-25Al 2 O 3 -50SiO 2 glasses, where a shift in the XANES pre-edge is observed as a function of the cation site 31 . In an attempt to confirm the above assumption we gather in .…”

Section: Aluminosilicatessupporting

confidence: 81%

Non network-former cations in oxide glasses spotted by Raman scattering

Hehlen

2020

Phys. Chem. Chem. Phys.

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Section: Aluminosilicatessupporting

confidence: 81%

Non network-former cations in oxide glasses spotted by Raman scattering

Hehlen

2020

Phys. Chem. Chem. Phys.

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“…The Tg does not respect the polymerization/optical basicity trend, because even if DiAn glasses are more depolymerized, they have a higher Tg than NA66.10. Indeed, Ca and Mg that are nominally considered network modifiers, have a valence of 2+, which allows them cross-linking species in the glass structure [charge compensator role; e.g., (Cicconi et al, 2016)]. The addition of vanadium induces a strong decrease of Tg for all compositions (see Table 1).…”

Section: Glass Physical Propertiesmentioning

confidence: 99%

Influence of Vanadium on Optical and Mechanical Properties of Aluminosilicate Glasses

Cicconi¹,

Lu²,

Uesbeck

et al. 2020

Front. Mater.

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V 2 O 5 was introduced up to 9 wt.% in a peralkaline alkaline earth aluminosilicate glass and up to 4.8 wt.% in two sodo aluminosilicate glasses, respectively, a peralkaline and a peraluminous one. This introduction had a strong effect on thermal properties, and in particular, on glass transition and crystallization temperatures of the peraluminous glass, which dropped by 89 K, while a moderate drop of ∼20 K was observed for the two other glasses. Still, the glass stability and the glass-forming ability stayed almost unmodified. The elastic properties measured by Brillouin spectroscopy show a decrease with added Vanadium for the depolymerized alkali earth aluminosilicate and the peraluminous sodo aluminosilicate. In contrast, the elastic properties remained unchanged for the peralkaline composition. Using optical absorption, the proportion of V 5+ , which is largely dominant, was found to follow the trend predicted using optical basicity considerations. A large photoluminescence emission, centered at ∼560 nm, was found for all glasses, upon excitation in the UV edge at both ∼280 and ∼350 nm. The emission band positions were relatively insensitive to the glass composition, whereas their intensities show variations of one order of magnitude between the sodium peralkaline composition and the calcium depolymerized glass. A too-high concentration of V 2 O 5 shows a quenching effect on the emission. Polarized and cross-polarized Raman spectroscopy allowed us to identify the different environments around the V 5+ O 4 tetrahedra. The highly polarizable V 5+ O 4 tetrahedra associated with two non-bridging oxygens, vibrating at 860 cm −1 , is proposed to be responsible for the more efficient charge transfer. At the opposite end, the formation of VO 4 -AlO 4 units is proposed to quench luminescence properties. Furthermore, we observed that, upon thermal treatment, the optical properties of the glasses are significantly modified without observable structural modifications or evolution of the elastic properties.

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“…The pre-edge feature A (inset of Figure d) is an important probe of the coordination environment at the absorbing center. , This small feature is attributed to the transition from the Ca 1s electron to the unoccupied Ca 3d hybrid states. In the case of CaCl 2 and CaCl 2 ·2H 2 O, the first coordination shell structure is a pseudo-octahedron with a shorter-distance on-axis direction.…”

Section: Resultsmentioning

confidence: 99%

“…Next, we compare the Ca K-edge XANES of three samples. the three main features in each spectrum are marked as A, B, and C for CaCl The pre-edge feature A (inset of Figure 1a) is an important probe of the coordination environment at the absorbing center [46][47] . This small feature is attributed to the transition from Ca The charge transfer increases the energy gap between the 1s and 4p unoccupied states and reduces the number of transitions that can be made.…”

Section: Peak Assignmentmentioning

confidence: 99%

Deciphering the Solvent Effect for the Solvation Structure of Ca²⁺ in Polar Molecular Liquids

Ren

Liu

et al. 2020

J. Phys. Chem. B

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Although the crystal structures for many inorganic compounds are readily available, researchers are still working hard to understand the relations between the structures and chemical properties in solutions, because that is where most of the chemical reactions take place. A huge amount of effort has been put on modeling the ion solvation structure, from the perspectives of both experiments and theories. In this study, the solvation structures of Ca 2+ ion in aqueous and alcohol solutions at different concentrations were carefully evaluated by Ca K-edge X-ray Absorption Near-Edge Structure (XANES) and Extended X-ray Absorption Fine Structure (EXAFS). Density functional theory (DFT) calculations were also performed to correlate with the experimental data, and then further extended to other similar systems. It was found that the number of coordination solvent molecules decreases with increasing Ca 2+ concentration and increasing solvent molecule sizes. From the EXAFS data, the first solvation shell of Ca 2+ split into two Ca-O distances in methanol solution and the counter ion Clmight also be within the first shell at high concentrations. For the first time, the effects of solvent with different polarities and sizes on the ion solvation environment were systematically evaluated.

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Ca neighbors from XANES spectroscopy: A tool to investigate structure, redox, and nucleation processes in silicate glasses, melts, and crystals

Cited by 20 publications

References 21 publications

Non network-former cations in oxide glasses spotted by Raman scattering

Non network-former cations in oxide glasses spotted by Raman scattering

Influence of Vanadium on Optical and Mechanical Properties of Aluminosilicate Glasses

Deciphering the Solvent Effect for the Solvation Structure of Ca²⁺ in Polar Molecular Liquids

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Ca neighbors from XANES spectroscopy: A tool to investigate structure, redox, and nucleation processes in silicate glasses, melts, and crystals

Cited by 20 publications

References 21 publications

Non network-former cations in oxide glasses spotted by Raman scattering

Non network-former cations in oxide glasses spotted by Raman scattering

Influence of Vanadium on Optical and Mechanical Properties of Aluminosilicate Glasses

Deciphering the Solvent Effect for the Solvation Structure of Ca2+ in Polar Molecular Liquids

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Product

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Deciphering the Solvent Effect for the Solvation Structure of Ca²⁺ in Polar Molecular Liquids