Steverustite, Pb<sub>5</sub><sup>2+</sup>(OH)<sub>5</sub>[Cu<sup>+</sup>(S<sup>6+</sup>O<sub>3</sub>S<sup>2–</sup>)<sub>3</sub>](H<sub>2</sub>O)<sub>2</sub>, a new thiosulphate mineral from the Frongoch Mine Dump, Devils Bridge, Ceredigion, Wales: description and crystal structure
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
Abstract Steverustite, ideally Pb 5 2+ (OH) 5 [Cu + (S 6+ O 3 S 2– ) 3 ](H 2 O) 2 , is a new supergene mineral from the Frongoch mine dump, Devils Bridge, Ceredigion, Wales. It generally forms fibrous fan-like bundles that occur in small cavities in quartz veins with other supergene species. Crystals are fibrous to acicular, elongated along [010], and are bounded by ( h 0 l ) faces too small to index reliably. It is transparent, colourless to white with a white streak, has a vitreous lustre, does not fluoresce under ultraviolet light and is brittle with a splintery fracture. The calculated density is 5.150 g/cm 3 , and the calculated mean refractive index is 1.94. The mineral is monoclinic, P2 1 /n, a 12.5631(7), b 8.8963(5), c 18.0132(11) Å, β 96.459(1)º, V 2000.5(3) Å 3 , Z = 4, a:b:c = 1.41217:1:2.02480. The seven strongest lines in the X-ray powder diffraction pattern are as follows: d (Å), I , ( h k l ): 3.934, 10, (Ī14); 3.934, 8, (Ī11); 3.348, 7, (313); 6.211, 6, (200); 4.797, 6, (211); 3.026, 6, (314); 2.837, 5, (016). Chemical analysis by electron microprobe gave PbO 72.59, SO 3 15.78, Cu 2 O 4.47, S 2– 6.32, H 2 O 4.83, O=S 2– –3.15, total 100.84 wt.% where the amount of H 2 O was determined by crystal-structure analysis. The resulting empirical formula is Pb 4.99 2+ Cu 0.96 + (S 6+ O 3 S 2– ) 3.03 (OH) 4.88 (H 2 O) 1.67 , based on O + OH + H 2 O + S 2 – = 18.67 a.p.f.u. (atoms per formula unit) with H 2 O = 1.67 a.p.f.u. (from crystal-structure solution and refinement). The crystal structure of steverustite was solved by direct methods and refined to R 1 = 2.7% for 3366 unique (Fo > 4σF) reflections. There are five distinct Pb2+ cations with coordination numbers from [8] to [11], all of which show stereoactive lone-pair behaviour and which form a strongly bonded cluster of composition [Pb 5 (OH) 5 ]. There is one Cu + cation triangularly coordinated by three S2– atoms that belong to three thiosulphate groups, forming a Cu + (S 6+ O 3 S 2– ) 3 group. The [Pb 5 (OH)5] units and [Cu(S 2 O 3 )3] groups occur at the vertices of interpenetrating 3 6 nets to form layers of composition [Pb 5 (OH) 5 Cu(S 2 O 3 ) 3 ] parallel to (010) which are linked by weaker bonds. Examination of the stereochemistry of thiosulphate and thionate structures shows that the combination of <S–O> and S–S distances are distinct for these two types of structures.
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 | 0.003 | 0.003 |
| Meta-epidemiology (narrow) | 0.008 | 0.006 |
| Meta-epidemiology (broad) | 0.007 | 0.003 |
| Bibliometrics | 0.002 | 0.005 |
| Science and technology studies | 0.004 | 0.004 |
| Scholarly communication | 0.005 | 0.005 |
| Open science | 0.005 | 0.003 |
| Research integrity | 0.005 | 0.006 |
| Insufficient payload (model declined to judge) | 0.001 | 0.001 |
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