From structure topology to chemical composition. XXVI. Crystal structure and chemical composition of a possible new mineral of the murmanite group (seidozerite supergroup), ideally Na<sub>2</sub>CaTi<sub>4</sub>(Si<sub>2</sub>O<sub>7</sub>)<sub>2</sub>O<sub>4</sub>(H<sub>2</sub>O)<sub>4</sub>, from the Lovozero alkaline massif, Kola Peninsula, Russia
Bibliographic record
Abstract
Abstract The crystal structure of a murmanite-related mineral (MRM) of the murmanite group (seidozerite supergroup), ideally Na 2 CaTi 4 (Si 2 O 7 ) 2 O 4 (H 2 O) 4 , from Mt. Pyalkimpor, the Lovozero alkaline massif, Kola Peninsula, Russia, was refined in space group P $ {\bar 1} $ with a = 5.363(2), b = 7.071(2), c = 12.176(5) Å, α = 92.724(3), β = 107.542(7), γ = 90.13(2)°, V = 439.7(4) Å 3 and R 1 = 5.72%. On the basis of electron-microprobe analysis, the empirical formula calculated on 22 (O + F), with two constraints derived from structure refinement, OH = 0.11 per formula unit (pfu) and H 2 O = 3.89 pfu, is (Na 2.12 K 0.07 Sr 0.01 ) Σ2.20 Ca 0.85 (Ti 3.01 Nb 0.39 Mn 0.20 Fe 2+ 0.19 Mg 0.17 Zr 0.01 Al 0.01 ) Σ3.98 (Si 4.20 O 14 )[O 3.90 F 0.10 ] Σ4 [(H 2 O) 3.89 (OH) 0.11 ] Σ4 {P 0.03 }, with Z = 1. It seems unlikely that {P 0.03 } belongs to MRM itself. The crystal structure of MRM is an array of TS blocks (Titanium-Silicate) connected via hydrogen bonds. The TS block consists of HOH sheets (H = heteropolyhedral, O = octahedral) parallel to (001). In the O sheet, the Ti-dominant M O 1 site and Ca-dominant M O 2 site give ideally (Ca□)Ti 2 pfu. In the H sheet, the Ti-dominant M H site and Na-dominant A P site give ideally Na 2 Ti 2 pfu. The M H and A P polyhedra and Si 2 O 7 groups constitute the H sheet. The ideal structural formula of MRM of the form A P 2 M H 2 M O 4 (Si 2 O 7 ) 2 (X O M,A ) 4 (X O A ) 2 (X P M,A ) 4 is Na 2 Ti 2 (Ca□)Ti 2 (Si 2 O 7 ) 2 O 4 (H 2 O) 4 . MRM is a Ca-rich and Na-poor analogue of murmanite, ideally Na 2 Ti 2 Na 2 Ti 2 (Si 2 O 7 ) 2 O 4 (H 2 O) 4 and a Na-rich and (OH)-poor analogue of calciomurmanite, ideally (Ca□)Ti 2 (Na□)Ti 2 (Si 2 O 7 ) 2 O 2 [O(OH)](H 2 O) 4 . MRM and (murmanite and calciomurmanite) are related by the following substitutions: O (Ca 2+ □) MRM ↔ O (Na + 2 ) mur and O (Ca 2+ □) MRM + H (Na + 2 ) MRM + O (O 2– ) MRM ↔ O (Na + □) cal + H (Ca 2+ □) cal + O [(OH) – ] cal . MRM is a possible new mineral of the murmanite group (seidozerite supergroup) where Ti + Mn + Mg = 4 apfu.
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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 | 0.002 | 0.001 |
| Meta-epidemiology (narrow) | 0.005 | 0.004 |
| Meta-epidemiology (broad) | 0.006 | 0.002 |
| Bibliometrics | 0.001 | 0.003 |
| Science and technology studies | 0.002 | 0.006 |
| Scholarly communication | 0.002 | 0.003 |
| Open science | 0.005 | 0.004 |
| Research integrity | 0.004 | 0.005 |
| Insufficient payload (model declined to judge) | 0.000 | 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; both teacher heads agree on what is shown here.
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".