The study of surface oxidation of tin(II) fluoride and chloride fluoride materials by Mössbauer spectroscopy: to oxidize or not to oxidize, that is the question
Bibliographic record
Abstract
Experimental methods designed to study the bulk of materials do not necessarily detect the changes taking place at the surface of the crystallites.For example, divalent tin-containing materials appear to be stable at ambient conditions in air, provided they are not hygroscopic, X-ray powder diffraction shows only the peaks of the expected tin(II) phase.However, we have observed that the Mössbauer spectrum of polycrystalline samples contain, in addition to the expected tin(II) peak(s), a small peak at 0 mm s relative to CaSnO 3 at ambient conditions, that can be attributed only to tin(IV) coordinated by oxygen.A detailed study of this phenomenon has shown that Mössbauer spectroscopy is quite sensitive for detecting thin layers of oxide at the surface of crystallites of tin(II).This phenomenon has been exploited for the study of spontaneous oxidation of various tin(II) fluoride and chloride-containing materials, some of these fluorides being the highest performance fluoride-ion conductors known to date.It was observed that passivation is quite efficient in the fluorides, and in the chloride fluorides that have all their tin(II) covalently bonded.On the other hand, the materials containing a mixture of covalently bonded tin(II) and the Sn 2+ stannous ion namely, the Ba 1-x Sn x Cl 1+y F 1-y solid solution, show a higher rate of oxidation, which is highly dependent on the method of preparation and the composition parameters, x and y.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| 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 source (direct Gemma or distilled Codex), 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".