From Structure Topology to Chemical Composition. XXX. Refinement of the Crystal Structure and Chemical Formula of Shkatulkalite, Na2Nb2Na3Ti(Si2O7)2O2(FO)(H2O)4(H2O)3, a Lamprophyllite-Group (Seidozerite Supergroup) TS-Block Mineral from the Lovozero Massif, Kola Peninsula, Russia
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 Shkatulkalite, ideally Na5TiNb2(Si2O7)2O3F(H2O)7, is a lamprophyllite-group (seidozerite supergroup) TS-block mineral from the Lovozero massif, Kola Peninsula, Russia. The crystal structure of shkatulkalite was refined as triclinic, space group P, a 5.464(1), b 7.161(1), c 15.573(1) Å, α 90.00(3), β 95.75(3), γ 90.00(3)°, V 606.3(4) Å3, R1 = 7.26%. The previously given chemical analysis has been modified to better fit the crystal structure: Nb2O5 24.15, TiO2 11.35, SiO2 27.22, BaO 1.15, SrO 2.20, MnO 1.68, CaO 0.46, K2O 0.29, Na2O 14.78, H2O 15.27, F 1.61, O = F −0.68, sum 99.48 wt.%; H2O was determined from structure-refinement results. The empirical formula was calculated on 25.27 (O + F) apfu (in accord with the crystal structure): (Na1.40Sr0.19Ba0.07K0.05)Σ1.71(Na2.86Mn0.10Ca0.07)Σ3.03(Nb1.62Ti1.27Mn0.11)Σ3Si4.03O24.52H15.11F0.75, Z = 1. The ideal structural formula is as follows: Na2Nb2Na3Ti(Si2O7)2O2(FO)(H2O)4(H2O)3. The crystal structure of shkatulkalite [basic structure type B5(LG)] is a combination of a TS (titanium-silicate) block and an I (intermediate) block. The TS block consists of HOH sheets (H-heteropolyhedral, O-octahedral). The TS block exhibits linkage and stereochemistry typical for the lamprophyllite group where Ti (+ Nb + Fe3+ + Mg) = 3 apfu. The O sheet is composed of Ti-dominant MO(1) and Na-dominant MO(2,3) octahedra. In the H sheet in shkatulkalite, Si2O7 groups link to Nb-dominant MH octahedra. The AP site occurs in the plane of the H sheet and splits into AP(1) and AP(2) sites, occupied by Na at 70% and Sr (less Ba and K) at 11%. The I block consists of H2O groups. The I block of shkatulkalite is topologically identical to those in the derivative structures of kazanskyite and nechelyustovite. The structure of the lamprophyllite-group mineral shkatulkalite has a counterpart structure in the murmanite group (Ti = 4 apfu): kolskyite, ideally Na2CaTi4(Si2O7)2O4(H2O)7 [basic structure type B7(MG)]: the two structures have TS blocks of different topology and similar I blocks, mainly occupied by H2O groups.
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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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 it