A solid-state NMR investigation of the colossal expansion material, Ag<sub>3</sub>Co(CN)<sub>6</sub>
Bibliographic record
Abstract
Presented here is a solid-state NMR investigation of the so-called “colossal expansion” material, Ag 3 Co(CN) 6 , a compound that exhibits some of the largest positive and negative thermal expansion properties reported. This study explores the 13 C, 15 N, and 59 Co NMR properties of this material at room temperature and at variable temperatures with the goal of probing the effects of this colossal expansion behaviour on these properties. We found that the flexible nature of the crystal framework leads to a distribution of electric field gradients, and that, oddly enough, no strong correlation is observed between the NMR parameters of Ag 3 Co(CN) 6 and its colossal expansion nature. The 59 Co isotropic chemical shift increased and the 59 Co nuclear quadrupolar coupling constant decreased with increasing temperature, but neither of these relationships were extraordinary when compared to other octahedral Co(III) complexes. The link between the colossal expansion and the NMR properties of Ag 3 Co(CN) 6 may be the distribution of lattice parameters and hence unusually broad features in the 59 Co NMR spectra. The high order of symmetry at the cobalt site resulted in a small quadrupolar coupling constant less than 1 MHz in magnitude. We also observed a | 1 J( 107/109 Ag, 15 N)| value of 96 Hz, the largest 107/109 Ag– 15 N coupling constant reported to date.
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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 | 0.001 | 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) | 0.000 | 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 teacher head, 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".