The crystal structure of tin sulphate, SnSO <sub>4</sub> , and comparison with isostructural SrSO <sub>4</sub> , PbSO <sub>4</sub> , and BaSO <sub>4</sub>
Bibliographic record
Abstract
The crystal structure of tin (II) sulphate, SnSO 4 , was obtained by Rietveld refinement using synchrotron high-resolution powder X-ray diffraction (HRPXRD) data. The structure was refined in space group Pbnm . The unit-cell parameters for SnSO 4 are a = 7.12322(1), b = 8.81041(1), c = 5.32809(1) Å, and V = 334.383(1) Å 3 . The average 〈Sn–O〉 [12] distance is 2.9391(4) Å. However, the Sn 2+ cation has a pyramidal [3]-coordination to O atoms and the average 〈Sn–O〉 [3] = 2.271(1) Å. If Sn is considered as [12]-coordinated, SnSO 4 has a structure similar to barite, BaSO 4 , and its structural parameters are intermediate between those of BaSO 4 and PbSO 4 . The tetrahedral SO 4 group has an average 〈S–O〉 [4] = 1.472(1) Å in SnSO 4 . Comparing SnSO 4 with the isostructural SrSO 4 , PbSO 4 , and BaSO 4 , several well-defined trends are observed. The radii, rM, of the M 2+ (=Sr, Pb, Sn, and Ba) cations and average 〈S–O〉 distances vary linearly with V because of the effective size of the M 2+ cation. Based on the trend for the isostructural sulphates, the average 〈Sn–O〉 [12] distance is slightly longer than expected because of the lone pair of electrons on the Sn 2+ cation.
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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".