Nitroplumbite, [Pb4(OH)4](NO3)4, a New Mineral with Cubane-Like [Pb4(OH)4]4+ Clusters from the Burro Mine, San Miguel County, Colorado, USA
Bibliographic record
Abstract
ABSTRACT Nitroplumbite (IMA2021-045a), [Pb4(OH)4](NO3)4, is a new mineral discovered at the Burro mine, Slick Rock district, San Miguel County, Colorado, USA. It occurs in a secondary efflorescent assemblage on asphaltite and montroseite- and corvusite-bearing sandstone in association with baryte, chalcomenite, and volborthite. The mineral forms as brown equant (pseudocubic) or colorless bladed crystals. The streak is white, luster is vitreous to greasy, Mohs hardness is 2½, tenacity is brittle, and fracture is conchoidal. Nitroplumbite is optically biaxial (–) with α = 1.790(5), β =1.820 (est.), and γ = 1.823 (est.) (white light); 2Vmeas = 35(1)°; optical orientation: Z = b; nonpleochroic. The calculated density is 5.297 g/cm3 for the empirical formula. Electron probe microanalysis provided the empirical formula Pb4.18(OH)4(N0.98O3)4. Nitroplumbite is monoclinic, space group Ia, a = 18.3471(7), b = 17.3057(4), c = 18.6698(8) Å, β = 91.872(3)°, V = 5924.7(4) Å3, and Z = 16. The crystal structure (R1 = 0.0509 for 11161 I > 2σI reflections) is the same as that previously determined for its synthetic analogue. It consists of isolated, internally bonded cubane-like [Pb4(OH)4]4+ clusters and isolated (NO3)– groups that are linked together by long Pb–O bonds and hydrogen bonds.
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How this classification was reachedexpand
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 | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.002 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.006 | 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 teacher head, 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".