Raman Scattering Study of Cation-Deficient Ba<i><sub>n</sub></i>(MoNb)<i><sub>n</sub></i><sub>-</sub><sub>δ</sub>O<sub>3</sub><i><sub>n</sub></i><sub>-</sub><i><sub>x</sub></i> and Related Perovskite-like Oxides
Bibliographic record
Abstract
The Raman scattering spectra of Ba 3 MoNbO 8.5 and Ba 7 Nb 4 MoO 20, two cation-deficient perovskite-like oxides, are presented for the first time and analyzed in an attempt to confirm the distribution of octahedra and tetrahedra proposed in recent structural investigations. The Raman spectra are discussed in relation to spectra of compounds of the hexagonal perovskite-like oxides with the general formula A n B n - δ O 3 n - x (δ ≥ 1, x ≥ 0). While the spectra of all compounds are found to be dominated by strong tetrahedral bands near 300 and 800 cm - 1, modes of octahedral symmetry are evident between 400 and 700 cm - 1 in those compounds which contain octahedral [BO 6 ] groups according to structural studies. The Raman spectrum of Ba 3 Nb 2 O 8 contains modes in the region attributed to vibrations of octahedral symmetry although it is stoichiometrically identical to the palmierite structure which has only tetrahedrally coordinated B-sites. This observation is in disagreement with structural work previously reported in the literature but provides strong corroborating evidence for a new study which indicates a variant stacking arrangement of hexagonal and cubic close-packed layers giving rise to an equal number of octahedrally and tetrahedrally coordinated B-sites in this compound.
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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) | 0.001 | 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".