Gas-Phase Reactions of Sulfur Hexafluoride with Transition Metal and Main Group Atomic Cations: Room-Temperature Kinetics and Periodicities in Reactivity
Bibliographic record
Abstract
Gas-phase reactions of SF(6) were investigated with 46 different atomic metal and main group cations at room temperature using an Inductively-Coupled Plasma/Selected-Ion Flow Tube (ICP/SIFT) tandem mass spectrometer. The atomic ions were produced at about 5500 K in the ICP source and allowed to decay radiatively and to thermalize by collisions with argon and helium atoms prior to reaction downstream in a flow tube in helium buffer gas at 0.35 +/- 0.01 Torr and 295 +/- 2 K. Rate coefficients and product distributions were measured for the reactions of fourth-row atomic ions from K(+) to Se(+), of fifth-row atomic ions from Rb(+) to Te(+) (excluding Tc(+)), and of sixth-row atomic ions from Cs(+) to Bi(+). The early transition metal ions react with SF(6) very efficiently (k/k(c) = 0.56-0.96) to produce MF(m)(+) (m = 1-4) and SF(n)(+) (n = 1-4) ions, whereas the late transition metal ions react much less efficiently (k/k(c) < 0.2) to form M(+)(SF(6)) adduct ions. Reactions of SF(6) with Ca(+), Sr(+), Ba(+), Ge(+), and As(+) proceed efficiently (k/k(c) = 0.35-0.85) through various channels, while all other main group metal ions are inert toward sulfur hexafluoride. Primary and secondary adduct formation was observed to exhibit equilibrium kinetics, and the standard free energy change for SF(6) addition is found to correlate with the efficiency of addition according to log[k/k(c)] = -8.7 + 7.8 log[-DeltaG(o)/(kcal mol(-1))]. Several MF(m)(+) ions were observed to react further with SF(6) to produce MF(m+k)(+), SF(n)(+), and MF(m)(+)(SF(6)) as secondary products.
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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) | 0.001 | 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".