Isomers of Protonated Octane, C<sub>8</sub>H<sub>19</sub><sup>+</sup>
Bibliographic record
Abstract
Ab initio calculations at the MP2/6-31G(d) level of theory have been performed to determine the geometries and relative energies of many isomers of protonated octane (also known as octonium or octanium ions). Five of the 18 structural isomers of octane were considered for protonation, as they provided C−C bonds containing all possible combinations of carbon substitution types (quaternary−tertiary, quaternary−secondary, etc.). All resulting isomers of C 8 H 19 + feature either a CHC or a CHH 3-center-2-electron (3c2e) bond, although barrierless dissociation into an ion−molecule complex was very common. Octonium ion properties such as relative energies, 3c2e bond geometries, Mulliken partial charges, and the frequency of the most intense infrared absorption, have also been calculated. Each property is correlated to the level of substitution of C atoms in the 3c2e bond. The proton affinities of individual bonds in octane range from 154 to 187 kcal mol -1 for C−C bonds and 139 to 150 kcal mol -1 for C−H bonds. Alkanium (carbonium) ions of greater than four carbons have never before been studied in this depth.
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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 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.006 | 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".