SULFATE MINERALS. I. BOND TOPOLOGY AND CHEMICAL COMPOSITION
Bibliographic record
Abstract
The crystal structure of an oxysalt mineral may be divided into two parts: (1) the structural unit , an array of high-bond-valence polyhedra that is usually anionic in character, and (2) the interstitial complex , an array of large low-valence cations, simple anions, (OH) and (H2O) groups that is usually cationic in character. The chemical compositions of interstitial complexes in sulfate minerals are explained and predicted using intrinsic properties such as polarity, Lewis acidity, coordination numbers and the average charge of oxygen atoms in the structural unit (average basicity). The interstitial complex can be characterized by its Lewis acidity , a measure of the electrophilic character of the complex, and the structural unit can be characterized by its range in Lewis basicity . Any complex structural unit [ M z +(H2O) n (OH) m (SO4) k ] can be divided into an acidic component of ( M z +ϕ n ) polyhedra and a basic component of (SO4) groups. The ligands of the acidic component are primarily bond-valence donors, and the O atoms of the basic component are bond-valence acceptors. Neutral structural units must arrange themselves such that their acidic and basic parts match each other in order to allow linkage via hydrogen bonds. Additional (H2O) groups between structural units are required where hydrogen bonds cannot be accepted directly by a donor atom of the basic part of the structural unit. The Lewis acidities of interstitial complexes in sulfate minerals range from 0.10 to 0.25 vu (valence units), with frequency maxima at 0.13, 0.17, 0.20–0.21 and 0.25 vu . These maxima correspond to average coordination-numbers of oxygen atoms in the basic component of the structural unit. Using the characteristic range in Lewis basicity of a structural unit and the maximum frequencies of Lewis acidities, the most probable number of bonds from the interstitial complex to the structural unit may be predicted using the valence-matching principle. This number allows prediction of the types of interstitial complexes for a given structural unit.
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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 | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.006 | 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".