Lauraniite, Cu6Cd2(SO4)2(OH)12·5H2O, a New Copper Cadmium Sulfate Mineral from the Laurani Mine, Bolivia
Bibliographic record
Abstract
ABSTRACT Lauraniite, Cu6Cd2(SO4)2(OH)12·5H2O, is a new mineral from the Laurani Mine, Aroma Province, La Paz Department, Bolivia, where it is found as a secondary mineral associated with serpierite and brochantite, on a matrix consisting of tennantite and chalcocite. Lauraniite occurs as bladed crystals up to 110 μm in length. Crystals are pale blue and transparent, with a vitreous luster and a white streak. Fracture is uneven. Cleavage is perfect on {100}. The calculated density is 3.40 g/cm3 based on the empirical formula. Optically, lauraniite is uniaxial (+) with α = 1.637(3), β = 1.638(3), γ = 1.638(3) (white light), 2V = 20(2)°, and orientation Z ≈ a. The empirical formula, based on data obtained from electron microprobe analysis, is Cu6.13(Cd1.62Zn0.24)(SO4)1.96(OH12.03Cl0.05)12.08·5.08H2O. Lauraniite is monoclinic, P21/c, a = 7.3200(15), b = 25.424(5), c = 11.283(2) Å, β = 91.62(3)°, V = 2099.0(7) Å3, and Z = 4. The crystal structure, determined using single-crystal data obtained using synchrotron radiation, refined to R1 = 0.0468% for 5999 observed reflections with Fo > 4σ(Fo). It is characterized by undulating, brucite-like sheets consisting of seven Cuϕ6 (ϕ: O2–, OH–, H2O) octahedra and two Cd(OH)6(H2O) polyhedra. Sheets are decorated on one side by corner-sharing SO4 tetrahedra. Linkages between adjacent sheets are provided by H-bonds.
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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 | 0.001 |
| 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".