Interactions between SF<sub>4</sub> and Fluoride: A Crystallographic Study of Solvolysis Products of SF<sub>4</sub>·Nitrogen-Base Adducts by HF
Bibliographic record
Abstract
Adducts between SF4 and a nitrogen base are easily solvolyzed by HF, yielding the protonated nitrogen base and fluoride. Salts resulting from the solvolysis of SF4·NC5H5, SF4·NC5H4(CH3), SF4·NC5H3(CH3)2, and SF4·NC5H4N(CH3)2 have been studied by Raman spectroscopy and X-ray crystallography. Crystal structures were obtained for pyridinium salts [HNC5H5(+)]F(-)·SF4 and [HNC5H5(+)]F(-)[HF]·2SF4, the 4-methylpyridinium salt [HNC5H4(CH3)(+)]F(-)·SF4, the 2,6-methylpyridinium salt [HNC5H3(CH3)2(+)]2[SF5(-)]F(-)·SF4, and 4-(dimethylamino)pyridinium salts [HNC5H4N(CH3)2(+)]2[SF5(-)]F(-)·CH2Cl2 and [NC5H4N(CH3)2(+)][HF2(-)]·2SF4. In addition, the structure of [HNC5H4(CH3)(+)][HF2(-)] was obtained. 4,4'-Bipyridyl reacts with SF4 and 1 and 2 equiv of HF to give the 4,4'-bipyridinium salts [NH4C5-C5H4NH(+)]F(-)·2SF4 and [HNH4C5-C5H4NH(2+)]2F(-)·4SF4, respectively. These structures exhibit a surprising range of bonding modalities and provide an extensive view of SF4 and its contacts with Lewis basic groups in the solid state. The interactions range from the strong F4S-F(-) bond in the previously observed SF5(-) anion to weak F4S---F(-), F4S(---F(-))2, and F4S(---FHF(-))2 dative bonds.
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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 | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 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 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".