“…According to previous articles that studied the effect of total Fe-content in sodium-silicate glasses, the reduced samples investigated here have a g = 2 signal shape similar to the one observed at higher iron content ([Fe 2 O 3 ] > 1 mol%). [17,18] In these high Fe-glasses, Fe 3+ -rich clusters have been shown by optical absorption and Mössbauer spectroscopic properties [49] and confirmed by neutron diffraction and numerical simulations. [50] The present study shows that, in reduced samples, residual Fe 3+ tends to segregate, with an EPR signature similar to that in concentrated glasses.…”
Section: Clustering Vs Isolated Sitesmentioning
confidence: 87%
“…[14][15][16] The attribution of the feature at g = 2 is less clear. [17] Different scenarios have been proposed: (i) a signal due to exchange-coupled pairs or clusters of more than two atoms [18] involving edge-or face-sharing Fe 3+ sites [16,19,20]. These clusters could be trimers [21] up to nano-clusters as in ferritine [22], nanoparticles [23] or obsidian wt.% glasses [7,24]; (ii) a paramagnetic signal due to Fe 3+ in axially distorted sites (E/D ~ 0) [19], this signal being enhanced by dipole-dipole interactions.…”
“…According to previous articles that studied the effect of total Fe-content in sodium-silicate glasses, the reduced samples investigated here have a g = 2 signal shape similar to the one observed at higher iron content ([Fe 2 O 3 ] > 1 mol%). [17,18] In these high Fe-glasses, Fe 3+ -rich clusters have been shown by optical absorption and Mössbauer spectroscopic properties [49] and confirmed by neutron diffraction and numerical simulations. [50] The present study shows that, in reduced samples, residual Fe 3+ tends to segregate, with an EPR signature similar to that in concentrated glasses.…”
Section: Clustering Vs Isolated Sitesmentioning
confidence: 87%
“…[14][15][16] The attribution of the feature at g = 2 is less clear. [17] Different scenarios have been proposed: (i) a signal due to exchange-coupled pairs or clusters of more than two atoms [18] involving edge-or face-sharing Fe 3+ sites [16,19,20]. These clusters could be trimers [21] up to nano-clusters as in ferritine [22], nanoparticles [23] or obsidian wt.% glasses [7,24]; (ii) a paramagnetic signal due to Fe 3+ in axially distorted sites (E/D ~ 0) [19], this signal being enhanced by dipole-dipole interactions.…”
“…Non-monotonic behavior T g vs. Fe content can be explained with the results of structural investigations. The environment of Fe(III) in soda-silica glasses doped with iron were detail studied by Dunaeva et al [23,30]. As the results of Mössbauer spectroscopy, EPR and XANES/EXAFS, it was shown that in the glasses with low iron content (under 4 wt.% Fe 2 O 3 ) CN N 4, moreover, in the region under 1 wt.% Fe 2 O 3 isolated Fe(III) predominate over clustered, in the area between 1 and 4 wt.% their quantities are comparable.…”
Section: Discussionmentioning
confidence: 99%
“…This method is analogous to one described in [23], so we believe that compositions of glasses correspond to the initial raw batch. The mixtures were prepared from analytically pure materials.…”
Section: Glassesmentioning
confidence: 99%
“…The vertical and horizontal error bars represent the uncertainties of the peak area determination and iron content, correspondingly. The maximal standard deviation for iron quantities was estimated from the results of EDX analysis for identical glasses [23].…”
We systematically study medium‐range structures including more than three neighboring atoms around iron ions (Fe2+ and Fe3+) in soda‐lime glass samples with low iron oxide concentrations (MFe2O3) and a wide number ratio of Fe2+ to all iron ions (Fe2+/ΣnFe). The precise medium‐range structures around iron ions in glass have not yet been revealed because of a lack of the appropriate measurement methods. To avoid this problem, we used element‐specific nuclear resonant inelastic scattering (NRIS) with synchrotron X‐rays to observe the vibrations of iron ions (57Fe). The vibrations are related to medium‐range structures with more than three neighboring atoms and to the potential asymmetry and the coordination environment, around iron ions. The NRIS method has high sensitivity and can measure over a wide concentration range. Linear combination fitting of the X‐ray absorption fine structure spectra, which measures only the first neighbors but is a faster than using the NRIS method, was also used additionally. A systematically produced set of glasses with 0.015–5 wt% MFe2O3 and 0–0.85 Fe2+/ΣnFe was measured with these methods. It was found that the soda‐lime glass possessed two different medium‐range structures with different iron ion valences (~2+ or ~3+), which were determined by the Fe2+/ΣnFe, and that these structures were generated during production of the glass. Moreover, these medium‐range structures were the same from 0.015 to 5 wt% MFe2O3.
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