Hydroxykenopyrochlore, (□,Ce,Ba)2(Nb,Ti)2O6(OH,F), a new member of the pyrochlore group from Araxá, Minas Gerais, Brazil
Bibliographic record
Abstract
ABSTRACT Hydroxykenopyrochlore, (□,Ce,Ba)2(Nb,Ti)2O6(OH,F), occurs in a weathered Nb-ore from alkaline-carbonatite complexes and pegmatites of the Brazilian shield mined by Compania Brasileira de Metalurgia e Mineração (CBMM), Araxá, Minas Gerais, Brazil. The mineral is a product of alkali metasomatism. It occurs as parts of granular grains up to 0.1 mm in size in association with Ba-bearing hydrokenopyrochlore. Hydroxykenopyrochlore is lemon yellow to yellow in color, non-fluorescent, and brittle. The hardness is 4½ on the Mohs scale. The calculated density is 4.36 g/cm3. It is cubic, Fd–3m, with cell parameters a 10.590(5) Å, V = 1187.6(10) Å3, and Z = 2. The strongest seven lines in the powder XRD pattern [d in Å (I/I0) hkl] are 6.06 (49) 111, 3.18 (27) 311, 3.05 (100) 222, 2.64 (29) 400, 1.870 (56) 440, 1.594 (50) 622, 1.213 (15) 662, and 1.182 (13) 840. The empirical formula derived from electron-microprobe analyses is [□1.117Ce0.532Nd0.035La0.021Pr0.010Sm0.003Y0.002Ba0.101Ca0.030Pb0.004Th0.061U0.007K0.040Na0.036]Σ2(Nb1.368Ti0.325P0.095Fe0.091Al0.082Zr0.039)Σ2[O4.719(OH)1.281]Σ6[(OH)0.846F0.154]. Hydroxykenopyrochlore is a member of the pyrochlore supergroup (class 4.DH.15 of Strunz & Nickel; class 8.2.1. of Dana). It is the vacancy-dominant analogue of hydroxycalciopyrochlore, (Ca,Na,U,□)2(Nb,Ti)2O6(OH), and the Nb-dominant analogue of hydroxykenomicrolite, (□,Na,Sb3+)2Ta2O6(OH), and of hydroxykenoelsmoreite, (□,Pb)2(W,Fe3+,Al)2(O,OH)6(OH).
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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".