CRYSTAL CHEMISTRY OF THE ROSENBUSCHITE GROUP
Bibliographic record
Abstract
The minerals of the rosenbuschite group are sorosilicates composed of a framework of 6- to 8-corner polyhedra and rows of Si2O7 dimers. The polyhedra combine into layers (O layers) and into ribbons by edge sharing. Heterogeneous layers (H layers), composed of the octahedra from the ribbons and the sorosilicate groups, alternate with the O layer into a layered HOH structure. The 6- to 8-corner polyhedra host a variety of cations: Na, Mg, Ca, Ti, Mn, Fe, Y, Zr, Nb and the REE. Substitutions among these elements affect the geometrical properties of the various polyhedra. Crystal-structure refinements (X-ray diffraction) have been done on five specimens of the rosenbuschite group: götzenite, hainite, kochite (a new member of the group), rosenbuschite and seidozerite. Detailed models for their site occupancies are derived by fitting scattering values of the sites to the chemical compo-sition, and the weighted bond-valence sums to valence sums in an integrated calculation procedure. Results of chemical analyses suggest a series of intermediate compositions between götzenite and kochite. This series may be described as a solid-solution series in which Zr substitutes for Ca in one structural position, götzenite being the Ca-rich end-member. Through substitution of Ti by Zr, still another solid-solution exists between kochite and rosenbuschite, with rosenbuschite as the Zr-rich member. The Ca → Zr substitution has significant effect on the size of the respective octahedron, as well as on the dimension and distortion of the adjacent polyhedra. The reduction in size of the Ca → Zr octahedron is partly compensated by an enlargement of the dimensions of the adjacent Ti octahedron. This change favors the Ti → Zr substitution at the latter site. Different degrees of distortion in the
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.
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 | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 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".