<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 Mg2.12Fe3.17Ge2.56O12 is a new germanate forming at 1 atm pressure in the MgO-Fe2O3- GeO2 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(Mg0.52Fe0.33)VI(Mg1.60Fe2.40)IV(Ge2.56Fe0.44)O12, 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 Ca2+- and Y3+-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 Ca2+). Cubic Mg2.35Y2.00Fe0.97Ge2.59O12 is a new garnet phase forming at 1 atm pressure in the MgO-Y2O3-Fe2O3-GeO2 system. Its crystal structure and cation distribution were also determined by singlecrystal X-ray diffraction: VIII(MgY2)VI(Mg1.35Fe0.56)IV(Ge2.59Fe0.41)O12, 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., VIIIAVIB4IVT3O12 and VIIIA3VIB2IVT3O12 respectively. As a consequence, the tetragonal phase forms in systems containing smaller cations, such as Mg2+, Fe3+, Ni2+, Co2+, whereas larger cations, such as Y3+, show a strong preference for the garnet phase.
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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) | 0.003 | 0.003 |
| Meta-epidemiology (broad) | 0.004 | 0.001 |
| Bibliometrics | 0.001 | 0.003 |
| Science and technology studies | 0.002 | 0.005 |
| Scholarly communication | 0.002 | 0.002 |
| Open science | 0.002 | 0.000 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.001 | 0.003 |
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".