PREDICTION OF CRYSTAL MORPHOLOGY OF COMPLEX URANYL-SHEET MINERALS. II. OBSERVATIONS
Bibliographic record
Abstract
The morphology of basal faces of uranyl-sheet minerals is predicted by considering the bond-valence deficiency of the chains of polyhedra, the shift between the layers, and the arrangement of the interstitial complexes between the layers. The sheet structural units of schoepite, [(UO2)8O2(OH)12](H2O)12, and fourmarierite, Pb[(UO2)4O3(OH)4](H2O)4, have the same underlying anion-topology. The stabilities of their edges differ because adjacent layers in schoepite are shifted by one chain of polyhedra, whereas adjacent layers are not shifted in fourmarierite. The minerals becquerelite, [7] Ca(H2O)4[(UO2)3O2(OH)3]2 (H2O)4, compreignacite, [7] K2(H2O)3 [(UO2)3O2(OH)3]2(H2O)4, billietite, [10] Ba(H2O)4[(UO2)3O2(OH)3]2 (H2O)3, protasite, [10] Ba(H2O)3[(UO2)3O3(OH)2], and masuyite, [10] Pb(H2O)3[(UO2)3O3(OH)2], all have structural units with the same basic aniontopology. The stabilities of their edges differ because of the different arrangements of interstitial species. In becquerelite, the interstitial cations are arranged in rows parallel to [010], whereas in billietite and compreignacite, the interstitial cations are arranged in rows parallel to [100]. For masuyite and protasite, the stability of their edges is defined by large differences in the bond-valence deficiencies of the chains of polyhedra with left and right terminations. The stabilities of edges in curite, Pb3[(UO2)8O8(OH)6](H2O)3, are dictated by the low bond-valence deficiencies of the chains of polyhedra parallel to [001] and [011], and by the arrangement of cations in rows parallel to [001]. Minerals of the carnotite group contain the structural unit [(UO2)2(V2O8)] 2‐ , and the stability of the edges of their sheets is determined by the low bond-valence deficiency of chains of polyhedra parallel to [010 and [110]. Minerals of the uranophane group are based on the [(UO2)SiO3(OH)] ‐ sheet, and the stabilities of their edges are more strongly affected by the bond-valence deficiency of the chains of polyhedra than by the arrangement of the interstitial cations, and by the shift in the sheets. All predictions are compared with the corresponding morphologies of crystals recorded by Atomic Force Microscopy (AFM), on images of crystals, and on crystal drawings from the (mainly older) mineralogical literature. All predictions are in good agreement with the observed morphology of the basal faces.
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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".