Composition‐dependent structural role of lead in aluminoborate and galloborate glasses: A solid‐state NMR study
Bibliographic record
Abstract
Abstract Investigations on binary lead‐bearing glass systems have shown that Pb 2+ functions as a charge compensator at low concentrations and can participate in network formation at higher loadings. We use multinuclear magnetic resonance spectroscopy to investigate the mechanism underlying this dual‐role nature of Pb 2+ in ternary lead‐borate glasses containing aluminum or gallium. 207 Pb nuclear magnetic resonance (NMR) spectra—in conjunction with charge‐balance calculations, bond‐valence principles, and precedents from crystalline lead‐borates—are interpreted in terms of high‐ and low‐coordinate Pb 2+ species, representing charge‐compensating “network modifier” sites and covalently‐bound “network forming” sites, respectively. Both high‐field 27 Al and 71 Ga magic‐angle spinning NMR spectra indicate the presence of substantial fractions of four, five, and six‐fold coordinated Al/Ga, reinforcing the isostructural nature of these elements. However, systematic differences in the boron speciation in Al‐ and Ga‐bearing glasses reveal that their size difference has a measurable effect on the short‐range structure in these glasses.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".