<i>P</i> 4/ <i>n</i> and <i>P</i> 4 <i>nc</i> long-range ordering in low-temperature vesuvianites
Why this work is in the frame
A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.
Bibliographic record
Abstract
Low-temperature vesuvianites crystallize in the two space groups P4/n or P4nc due to different arrangements of Ca-dodecahedra and M2+,3+ square pyramids that form strings along the fourfold axes. Long-range ordered vesuvianites of acentric P4nc symmetry may have the same diffraction symmetry as centrosymmetric disordered P4/nnc vesuvianites. In contrast, P4/n long-range ordered vesuvianites exhibit glide plane violating reflections and can easily be identified. We report the first successful Xray single-crystal structure refinement of a P4nc vesuvianite, a = 15.487(2), c = 11.764(2) Å from the N’chwaning II mine of the Kalahari manganese fields (RSA). This untwinned crystal has Cu2+ and Mn2+, Mn3+ forming the square pyramid and exhibits an acentric ordering pattern with 85% string A and 15% string B. This is compared to a reinvestigation of the structure of a P4/n vesuvianite from Asbestos Quebec (Canada), a = 15.531(2), c = 11.817(2) Å. The crystal is composed of a merohedral (110) twin with a close to 1:1 twin ratio and has mainly Fe3+ in square pyramidal coordination. In this centric structure, string A is 84% and string B is 16% occupied. Criteria to determine the symmetry of low-temperature vesuvianites, studied by diffraction experiments, are discussed.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.002 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 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 it