New structures of hydronium cation clusters
Bibliographic record
Abstract
Four new hydronium ion structures are investigated by means of quantum mechanical calculations at the DFT/B3LYP6-311+G(2d,2p) level of theory. There exist experimental crystallographic hydronium cations (H 11 O 5 + ) of two different geometrical structures, one BEXFEQ (acyclic) and one IYEPEH (cyclic). Molecular calculations reveal their relative stability. Another hydronium cation NEBDII (H 15 O 7 + ) when optimized reveals a totally new and unexpected structure. All three optimized structures are shown to be quite stable as judged by their binding energies, and therefore may possibly be found in solution. A main result of this article is the discovery of three new optimized structures of hydronium ions, all of which are preferentially ring structures. The optimized structure of H 15 O 7 + is a cube lacking a vertex. Putting a water molecule at the “empty” vertex leads by energy optimization to a structure of H 17 O 8 + which has the approximate symmetry of a cube. This cubic structure, as judged by its fragments, is one of the most interesting of the hydronium ions studied in this paper. The addition of H 3 O + to a group of seven neutral molecules in the hypothetical reaction H 3 O + + 7 H 2 O → H 17 O 8 + induces two water molecules to each capture a proton at the expense of two other water molecules (converting them into hydroxyl anions) leading to a cluster with the formula [ H 3 O + 0.7 ] 3 [ H 2 O ] 3 + 0.1 [ OH − 0.6 ] 2 , where the superscripts are the integrated QTAIM atomic charges (in atomic units) on the respective species (inside the bracket) or on groups of a given species (outside the bracket). The cubic arrangement of 3H 3 O + .3H 2 O.2OH − is accompanied with a significant redistribution of charge: Each hydronium cation carries ca. +0.7 au, the hydroxyl anions only around –0.6 au each, while the water molecules remain quasi-neutral with a slight positive charge.
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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 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.005 | 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".