Crystal Structure and Physical Properties of RbNb<sub>4</sub>Br<sub>11</sub>
Bibliographic record
Abstract
Abstract RbNb4Br11 was obtained by a solid state reaction of niobium powder, NbBr5 and RbBr in a sealed niobium tube at 500 °C. It crystallizes in the orthorhombic space group Pmma with a = 1699.5(1), b = 726.7(1), c = 694.5(1) pm, V = 857.6(1)·106 pm3, Z = 2 and is isotypic with CsNb4Br11. Four niobium atoms build a cluster in the shape of a rhombus with bonding distances of 295 pm (Nb1–Nb2) and 304 pm (Nb2–Nb2), respectively. The structure consists of [{Nb4}Br6iBr10/2a–a]–cluster complex anions that are interconnected by two common edges and two faces to the next cluster complexes, thus forming a 2D undulated layer structure. The Rb+ ion is coordinated by 12 Br– ions in the shape of an anticuboctahedron. Electronic structure calculations indicate the presence of a band gap of approximately 0.33 eV. This is experimentally confirmed by an electrical conductivity measurement revealing a slightly higher gap of 0.46 eV.
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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) | 0.002 | 0.001 |
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".