THE STRUCTURES OF TWO NOVEL Sn2+ OXYSALTS FOUND WITH ROMARCHITE AND HYDROROMARCHITE AS CORROSION PRODUCTS OF PEWTER ARTIFACTS
Bibliographic record
Abstract
The crystal structures of an anthropogenic Sn2+ silicate, Sn6O4(SiO4), hexagonal, space group P63mc, a 7.3742(4), c 11.9598(10) Å, V 563.23(6) Å3, Z = 2, Dcalc 5.12 g/cm3, and an anthropogenic Sn2+ sulfate, Sn6O4(SO4)(OH)2, orthorhombic, space group Pbca, a 14.0071(8), b 12.5016(7), c 14.5030(9) Å, V 2539.6(3) Å3, Z = 8, Dcalc 4.74 g/cm3, were refi ned by full-matrix least-squares techniques on the basis of F2 to agreement indices R1 (Sn2+ silicate and Sn2+ sulfate) of 3.0 and 4.2%, calcu-lated for 704 and 3281 unique observed refl ections (|Fo | ≥ 4F), and wR2 of 5.5 and 11.0 % for all data, respectively. Intensity data were collected at room temperature using MoK radiation and a CCD-based area detector. Both structures contain the [Sn68] cluster [: O2 – or (OH)–], which has been found in several stannous compounds, and which can be derived from the structure of fl uorite. These two compounds occur with romarchite, SnO, and hydroromarchite, Sn3O2(OH)2, on pewter bowls that had become corroded in cold freshwater for approximately 160 years.
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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 | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 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".