A RE-EVALUATION OF THE STRUCTURE OF WEEKSITE, A URANYL SILICATE FRAMEWORK MINERAL
Bibliographic record
Abstract
The structure of weeksite, K_(1.26)Ba_(0.25)Ca_(0.12)[(UO_2)_2(Si_5O_(13))]H_2O, orthorhombic, a 14.209(2), b 14.248(2), c 35.869(4) Å, V 7262(2) Å^3, space group Cmmb, has been solved by direct methods using data collected with MoKα X-radiation and a CCD-based detector and refined by full-matrix least-squares techniques, on the basis of F^2 for all unique reflections, to an agreement factor (R_1) of 7.0% and a goodness-of-fit (S) of 1.04, calculated using the 1565 unique observed reflections (F_o ≤ 4σ_F). The structure contains four unique U^(6+) positions, each of which is part of a nearly linear (UO_2)^(2+) uranyl ion. The uranyl ions (Ur) are further coordinated by five atoms of oxygen arranged at the equatorial corners of UrO_5 pentagonal bipyramids. There are ten silicon atoms, each of which is tetrahedrally coordinated by oxygen atoms. The uranyl polyhedra share equatorial edges to form chains, which in turn share polyhedron edges with silicate tetrahedra. The uranyl silicate chains are linked to crankshaft-like chains of vertex-sharing silicate tetrahedra, resulting in layers that are connected by the sharing of vertices between silicate tetrahedra to form an open framework. Potassium, barium, calcium and H_2O are located in the channels within the uranyl silicate framework. Displacement of some atoms from their corresponding special positions indicates that the results represent an average structure.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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".