# Chemistry Bond Lengths Benchmark (Public Export)

Date: 2026-02-27
Originator: FluxMateria
Machine-readable artifacts: `chemistry_bond_lengths_benchmark.json`, `chemistry_bond_lengths_benchmark.csv`

## Methodology

Bond lengths predicted from first principles using the FluxMateria geometric engine.
Zero fitted parameters. All predictions deterministic and fully reproducible.

## Headline Metrics

| Metric | Value |
|---|---|
| Bonds validated | 55 |
| Mean \|error\| | 0.1296% |
| Median \|error\| | 0.1213% |
| Max \|error\| | 0.3176% |
| Within 0.5% | 55/55 |
| Within 1.0% | 55/55 |

## Top-10 Largest Errors

| Bond | Pred (pm) | Exp (pm) | Error% |
|---|---|---|---|
| C-C | 154.0 | 153.5 | +0.318% |
| F-F | 140.8 | 141.2 | -0.313% |
| C-F | 135.8 | 135.4 | +0.309% |
| C-Br | 197.2 | 196.6 | +0.307% |
| I-O | 201.6 | 201.0 | +0.305% |
| H-H | 73.9 | 74.1 | -0.302% |
| Cl-Cl | 198.3 | 198.8 | -0.258% |
| N-F | 136.3 | 136.0 | +0.256% |
| I-H | 161.3 | 160.9 | +0.226% |
| O-O | 147.8 | 147.5 | +0.213% |

## All Rows

| Bond | Pred (pm) | Exp (pm) | Error% |
|---|---|---|---|
| B-B | 169.7 | 170.0 | -0.155% |
| B-Br | 188.8 | 189.0 | -0.126% |
| B-Cl | 175.0 | 175.0 | -0.008% |
| B-F | 130.0 | 130.0 | +0.018% |
| B-H | 118.8 | 119.0 | -0.186% |
| B-S | 180.8 | 181.0 | -0.097% |
| Br-Br | 228.1 | 228.5 | -0.187% |
| Br-Cl | 213.7 | 213.8 | -0.043% |
| Br-H | 141.2 | 141.4 | -0.120% |
| C-Br | 197.2 | 196.6 | +0.307% |
| C-C | 154.0 | 153.5 | +0.318% |
| C-Cl | 178.9 | 178.6 | +0.152% |
| C-F | 135.8 | 135.4 | +0.309% |
| C-H | 109.2 | 109.4 | -0.157% |
| C-I | 213.6 | 214.0 | -0.183% |
| C-N | 147.7 | 147.4 | +0.195% |
| C-O | 142.7 | 142.6 | +0.069% |
| C-S | 181.3 | 181.4 | -0.040% |
| C-Si | 187.4 | 187.0 | +0.206% |
| Cl-Cl | 198.3 | 198.8 | -0.258% |
| Cl-H | 127.5 | 127.5 | -0.002% |
| Cl-P | 204.2 | 204.3 | -0.057% |
| Cl-Si | 202.3 | 202.0 | +0.150% |
| F-F | 140.8 | 141.2 | -0.313% |
| F-H | 91.6 | 91.7 | -0.121% |
| F-P | 157.2 | 157.0 | +0.141% |
| F-S | 158.0 | 158.0 | -0.028% |
| F-Si | 156.3 | 156.1 | +0.153% |
| H-H | 73.9 | 74.1 | -0.302% |
| I-Br | 248.6 | 248.5 | +0.031% |
| I-Cl | 232.2 | 232.1 | +0.056% |
| I-H | 161.3 | 160.9 | +0.226% |
| I-I | 266.6 | 266.6 | +0.010% |
| I-O | 201.6 | 201.0 | +0.305% |
| N-Cl | 175.6 | 175.3 | +0.176% |
| N-F | 136.3 | 136.0 | +0.256% |
| N-H | 101.3 | 101.2 | +0.089% |
| N-N | 144.5 | 144.5 | -0.026% |
| N-O | 139.9 | 140.0 | -0.088% |
| N-Si | 174.0 | 174.0 | -0.012% |
| O-Cl | 170.3 | 170.0 | +0.186% |
| O-F | 142.1 | 142.0 | +0.057% |
| O-H | 95.8 | 95.8 | -0.023% |
| O-O | 147.8 | 147.5 | +0.213% |
| P-Br | 221.9 | 222.0 | -0.046% |
| P-H | 141.9 | 141.9 | -0.028% |
| P-P | 220.7 | 221.0 | -0.152% |
| S-Cl | 207.1 | 207.0 | +0.045% |
| S-H | 133.7 | 133.6 | +0.110% |
| S-S | 204.9 | 205.0 | -0.039% |
| S-Si | 214.5 | 215.0 | -0.210% |
| Se-Se | 231.9 | 232.0 | -0.064% |
| Si-Br | 216.1 | 216.0 | +0.063% |
| Si-H | 147.7 | 148.0 | -0.175% |
| Si-Si | 234.1 | 234.0 | +0.042% |

## Sources

1. CRC Handbook of Chemistry and Physics, 97th Edition.
2. M.D. Morse et al., Utah Morse R2PI spectroscopy.
3. NIST Chemistry WebBook, webbook.nist.gov.