Prediction of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>o</mml:mi> <mml:mo>−</mml:mo> <mml:msub> <mml:mi mathvariant="normal">N</mml:mi> <mml:mn>16</mml:mn> </mml:msub> </mml:mrow> </mml:math> : A layered polymeric nitrogen phase
Bibliographic record
Abstract
Nitrogen allotropes, especially under extreme conditions, play a crucial role in understanding atomic configurations and driving innovations in high-energy materials. The phase composition of layered polymeric nitrogen (LP-N) remains unresolved, with Pba2, $C2$/c, and Pccn structures proposed as candidates. However, their relative stabilities and ambiguous x-ray-diffraction (XRD) patterns---consistent with experimental data but not definitely---along with multiple possible explanations, have been topics of ongoing debate, particularly under varying pressures. In this study, we present an unexpected orthorhombic phase, $o\ensuremath{-}{\mathrm{N}}_{16}$, predicted using machine-learning driven swarm-intelligence approach. Gibbs free-energy calculations, kinetic barrier analysis during decompression, and simulated XRD patterns reveal $o\ensuremath{-}{\mathrm{N}}_{16}$ and Pba2 as dominant LP-N phases at elevated pressures, with a partial transition from $o\ensuremath{-}{\mathrm{N}}_{16}$ to $C2$/c upon decompression. Notably, the relative stabilities of nitrogen allotropes cg-N, $o\ensuremath{-}{\mathrm{N}}_{16}, C2$/c, and Pccn are dictated by configurational and conformational isomerism of armchair chains and interchain bonding. These findings shed light on the evolution of atomic configurations under high-pressure conditions. Beyond its favorable energy density, $o\ensuremath{-}{\mathrm{N}}_{16}$ exceeds all polymeric nitrogen structures in terms of detonation velocity and detonation pressure.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.003 | 0.003 |
| Meta-epidemiology (narrow) | 0.001 | 0.002 |
| Meta-epidemiology (broad) | 0.001 | 0.003 |
| Bibliometrics | 0.000 | 0.003 |
| Science and technology studies | 0.001 | 0.002 |
| Scholarly communication | 0.001 | 0.002 |
| Open science | 0.003 | 0.003 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.072 | 0.005 |
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; both teacher heads agree on what is shown here.
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".