Reversible Reconstructive Phase Transition of Ba<sub>2</sub>SnSe<sub>5</sub>: A New High Temperature Modification with Completely Different Structural Motifs
Bibliographic record
Abstract
A new modification of Ba(2)SnSe(5) was prepared by high temperature synthesis. In contrast to its low temperature modification that adopts the orthorhombic space group P2(1)2(1)2(1), the new beta-Ba(2)SnSe(5) crystallizes in the monoclinic system, space group P2(1)/c, with the lattice parameters a = 9.3949(6) A, b = 8.8656(6) A, c = 12.5745(7) A, beta = 113.299(4) degrees, V = 961.9(1) A(3), Z = 4. alpha-Ba(2)SnSe(5) is comprised of Sn(3)Se(10)(8-) units, SnSe(4)(4-) tetrahedra, and isolated Se(3)(2-) units, while beta-Ba(2)SnSe(5) contains only SnSe(5)(4-) units, wherein Sn is tetrahedrally coordinated by four Se atoms. The fifth Se atom is connected to one Se atom of the SnSe(4)(4-) tetrahedron, thereby forming a Se(2)(2-) dumbbell. Different band gaps are a result of the different structure motifs, which are reflected in different colors of the two Ba(2)SnSe(5) modifications, the alpha-form being dark brown and the beta-form being red.
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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".