Penikisite, BaMg<sub>2</sub>Al<sub>2</sub>(PO<sub>4</sub>)<sub>3</sub>(OH)<sub>3</sub>, isostructural with bjarebyite
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
The bjarebyite group of minerals, characterized by the general formula BaX(2)Y(2)(PO(4))(3)(OH)(3), with X = Mg, Fe(2+) or Mn(2+), and Y = Al or Fe(3+), includes five members: bjarebyite BaMn(2+) (2)Al(2)(PO(4))(3)(OH)(3), johntomaite BaFe(2+) (2)Fe(3+) (2)(PO(4))(3)(OH)(3), kulanite BaFe(2+) (2)Al(2)(PO(4))(3)(OH)(3), penikisite BaMg(2)Al(2)(PO(4))(3)(OH)(3), and perloffite BaMn(2+) (2)Fe(3+) (2)(PO(4))(3)(OH)(3). Thus far, the crystal structures of all minerals in the group, but penikisite, have been determined. The present study reports the first structure determination of penikisite (barium dimagnesium dialuminium triphosphate trihydroxide) using single-crystal X-ray diffraction data of a crystal from the type locality, Mayo Mining District, Yukon Territory, Canada. Penikisite is isotypic with other members of the bjarebyite group with space group P2(1)/m, rather than triclinic (P1 or P-1), as previously suggested. Its structure consists of edge-shared [AlO(3)(OH)(3)] octa-hedral dimers linking via corners to form chains along [010]. These chains are decorated with PO(4) tetra-hedra (one of which has site symmetry m) and connected along [100] via edge-shared [MgO(5)(OH)] octa-hedral dimers and eleven-coordinated Ba(2+) ions (site symmetry m), forming a complex three-dimensional network. O-H⋯O hydrogen bonding provides additional linkage between chains. Microprobe analysis of the crystal used for data collection indicated that Mn substitutes for Mg at the 1.5% (apfu) level.
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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.004 | 0.003 |
| Meta-epidemiology (broad) | 0.004 | 0.002 |
| Bibliometrics | 0.002 | 0.004 |
| Science and technology studies | 0.003 | 0.002 |
| Scholarly communication | 0.002 | 0.004 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.003 | 0.004 |
| 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 it