<sup>VIII</sup> (Mg,Fe) <sub>0.85</sub> <sup>VI</sup> (Mg,Fe) <sub>4</sub> <sup>IV</sup> (Fe,Ge) <sub>3</sub> O <sub>12</sub> : A new tetragonal phase and its comparison with garnet
Bibliographic record
Abstract
Tetragonal Mg 2.12 Fe 3.17 Ge 2.56 O 12 is a new germanate forming at 1 atm pressure in the MgO-Fe 2 O 3- GeO 2 system. It is an analogue of the high-pressure silicate mineral TAPP occurring as inclusions in diamonds of lower-mantle origin. Its crystal structure was determined by X-ray diffraction using single-crystals grown from a potassium molybdate flux. It crystallizes in the I4̄2d space group with a = 6.8153(4) Å, c = 18.669(2) Å, Z = 4. The refinement of its cation distribution, VIII (Mg 0.52 Fe 0.33 ) VI (Mg 1.60 Fe 2.40 ) IV (Ge 2.56 Fe 0.44 )O 12 , shows the presence of a partially filled (85%) dodecahedral site characterized by an unusual geometry with two very different bond lengths [2.169 Å (×4) and 2.609 Å (×4)]. The structure determinations of the Ca 2+ - and Y 3+ -substituted phases show that the larger cations are completely partitioned in the dodecahedral site, increasing its occupancy slightly (up to 92% in the case of Ca 2+ ). Cubic Mg 2.35 Y 2.00 Fe 0.97 Ge 2.59 O 12 is a new garnet phase forming at 1 atm pressure in the MgO-Y 2 O 3 -Fe 2 O 3 -GeO 2 system. Its crystal structure and cation distribution were also determined by singlecrystal X-ray diffraction: VIII (MgY 2 ) VI (Mg 1.35 Fe 0.56 ) IV (Ge 2.59 Fe 0.41 )O 12 , Ia3̄d space group, a = 12.232(1) Å, Z = 8. In spite of similarities in their chemical compositions, the tetragonal and garnet phases are structurally distinct, with different ratios of dodecahedral to octahedral sites, viz., VIII A VI B 4 IV T 3 O 12 and VIII A 3 VI B 2 IV T 3 O 12 respectively. As a consequence, the tetragonal phase forms in systems containing smaller cations, such as Mg 2+ , Fe 3+ , Ni 2+ , Co 2+ , whereas larger cations, such as Y 3+ , show a strong preference for the garnet phase.
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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 | 0.000 | 0.000 |
| 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) | 0.004 | 0.001 |
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".