Syntheses, Vibrational Spectra, and Theoretical Studies of the Adamantanoid Sn<sub>4</sub>Ch<sub>10</sub><sup>4</sup><sup>-</sup> (Ch = Se, Te) Anions: X-ray Crystal Structures of [18-Crown-6-K]<sub>4</sub>[Sn<sub>4</sub>Se<sub>10</sub>]·5en and [18-Crown-6-K]<sub>4</sub>[Sn<sub>4</sub>Te<sub>10</sub>]·3en·2THF
Bibliographic record
Abstract
The salts [18-crown-6-K](4)[Sn(4)Se(10)].5en and [18-crown-6-K](4)[Sn(4)Te(10)].3en.2THF were isolated upon addition of THF to the ethylenediamine (en) extracts of the alloys KSn(0.90)Se(1.93) and K(4)Sn(4)Te(10) that had been extracted in the presence of 18-crown-6 (1,4,7,10,13,16-hexaoxacyclooctadecane). The Sn(4)Te(10)(4-) anion has been structurally characterized for the first time by a single-crystal X-ray diffraction study of [18-crown-6-K](4)[Sn(4)Te(10)].3en.2THF: P2(1)/n, a = 22.420(5) A, b = 19.570(4) A, c = 24.680(5) A, beta = 96.90(3)(o), Z = 4, and R(1) = 0.0468 at -183 degrees C. In addition to Si(4)Te(10)(4-) and Ge(4)Te(10)(4-), the Sn(4)Te(10)(4-) anion represents the only other known group 14 adamantanoid telluride. The X-ray crystal structure determination of the related [18-crown-6-K](4)[Sn(4)Se(10)].5en salt has also been determined: P2(1)/n, a = 22.003(2) A, b = 18.966(2) A, c = 24.393(2) A, beta = 97.548(8)(o), Z = 4, and R(1) = 0.0843 at -123 degrees C. The anion geometries are of the adamantanoid type where the Sn(IV) atoms occupy the bridgehead positions and the chalcogen atoms occupy the bridging and terminal sites. The energy minimized geometries of Sn(4)Ch(10)(4-) have also been determined using density functional theory (DFT). Mayer bond order analyses, Mayer valencies, and empirical bond valencies indicate that the terminal Sn-Ch bonds have significant multiple bond character, with the terminal Sn-Se bond having more multiple bond character than the terminal Sn-Te bond. The vibrational frequencies of the Sn(4)Se(10)(4-) and Sn(4)Te(10)(4-) anions have been calculated using DFT methods, allowing the Raman spectrum of Sn(4)Se(10)(4-) to be fully assigned.
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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) | 0.002 | 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".