The local environment of trivalent lanthanide ions in sodium silicate glasses: A neutron diffraction study using isotopic substitution

Wilding, Martin C.; Badyal, Y. S.; Navrotsky, Alexandra

doi:10.1016/j.jnoncrysol.2007.06.071

Cited by 26 publications

(15 citation statements)

References 45 publications

(49 reference statements)

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“…Nonetheless, the position of the 1 atm LaAS glass in Fig. 7 is consistent with a recent neutron diffraction study that derived a coordination number of 6 for La in Na silicate glasses (Wilding et al, 2007). We observe a 10-20% increase in the La coordination number between 1 atm and 8 GPa.…”

Section: X-ray Absorption Fine-structure Spectroscopy Resultssupporting

confidence: 90%

Cation field strength effects on high pressure aluminosilicate glass structure: Multinuclear NMR and La XAFS results

Kelsey

Stebbins

Singer

et al. 2009

Geochimica et Cosmochimica Acta

131

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Section: X-ray Absorption Fine-structure Spectroscopy Resultssupporting

confidence: 90%

Cation field strength effects on high pressure aluminosilicate glass structure: Multinuclear NMR and La XAFS results

Kelsey

Stebbins

Singer

et al. 2009

Geochimica et Cosmochimica Acta

131

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“…The ∼6 O in the Lu first coordination sphere compare well with data reported for Yb-, Er-, Dy-, and La-bearing silicate glasses (29)(30)(31) and for Cm-bearing borosilicate glass (32). The Si detected as next neighbors in Lu/silica correspond to silica units, possibly binding the Lu polyhedra by sharing edge(s) and corners (R O-Si ) 1.64 Å) (31), with geometries ranging from aligned to bent.…”

Section: Results and Interpretationsupporting

confidence: 86%

“…This binding mode may account for R Lu-Si3 by slightly tilting the Si tetrahedron. Finally, the Lu-Si distance of 3.50(2) Å is close to the value reported for Dy-doped silicate glasses (R Dy-Si ) 3.60 Å) (31), and to the value expected for corner sharing in a bent geometry. Important cancellation effects may arise in the vicinity of Lu from these various geometries and lead to low numbers of detected backscatterers.…”

Section: Results and Interpretationsupporting

confidence: 85%

Sites of Lu(III) Sorbed to and Coprecipitated with Hectorite

Finck

Schlegel

Bosbach

2009

Environ. Sci. Technol.

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The Lu(III) binding mechanisms by trioctahedral smectite hectorite in aqueous systems were investigated by extended X-ray absorption fine structure (EXAFS) spectroscopy. Coprecipitated hectorite (Lu755Hec), its precursor phase (Lu/Brucite), and the surface sorbed hectorite (Lu/SHCa1) were prepared as oriented samples to collect polarized EXAFS (P-EXAFS) data. EXAFS analysis indicated that Lu(III) is 6-fold coordinated by oxygen in Lu/Brucite and in Lu755Hec, and surrounded by Mg/Si shells. The angular dependence of the O and Mg coordination numbers for Lu/Brucite hinted an Lu(III) incorporation in brucite layers. Mg and Si cationic shells were detected at distances suggesting a clay-like octahedral environment in Lu755Hec. EXAFS data for Lu/SHCa1 were consistent with Lu(III) forming inner-sphere surface complexes at hectorite platelets edges, but slightly above/below the octahedral plane. Finally, Lu(III) polyhedra share edge(s) and corner(s) with Si tetrahedra upon sorption to silica (Lu/Silica). Lu(III) binding to silicate oligomers or to silicate groups of the clay basal planes and formation of Lu(III) surface complexes during the coprecipitation experiment are marginal.

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“…For instance, the near constancy in T g has been attributed either to a controlling effect of the RE-ions on diffusion and viscosity [30] or from a decreased difference in bond strengths for bridging oxygen (BO) and NBO ions [24]. Although relatively sparse and generally not conducted for large series of samples, structural studies have mostly been carried out using Xray or neutron powder diffraction [31][32][33] and solid-state nuclear magnetic resonance (NMR) [15,[24][25][26][27][28][29][34][35][36][37][38][39], IR and Raman [7,[37][38][39][40][41] spectroscopies. However, increased detailed structural knowledge about RE-based glasses is needed to have a non-superficial understanding of the compositional variations of their physical properties.…”

Section: Introductionmentioning

confidence: 99%