A general-purpose language model just walked into the chemistry lab and held its own against software that’s been purpose-built for molecular analysis. Anthropic published a research report on June 5 titled “Making Claude a chemist,” demonstrating that Claude Opus 4.7 can perform nuclear magnetic resonance spectroscopy tasks at a level that matches, and in some cases exceeds, dedicated NMR tools like ChemDraw 25.0.2 and MestReNova 17.0.0.
The numbers tell the story
Anthropic’s study tested Opus 4.7 across 20 compounds sourced from recent synthetic chemistry preprints, evaluating both forward prediction (simulating what a spectrum should look like given a molecular structure) and inverse structure elucidation (working backward from spectral data to figure out the molecule).
On hydrogen NMR shifts, Opus 4.7 posted the lowest average error at plus or minus 0.079 ppm. For carbon shifts, it tied with MestReNova at plus or minus 1.37 ppm. To translate that into something meaningful: parts per million is the standard unit for measuring chemical shifts in NMR, and errors under 0.1 ppm on hydrogen data represent genuinely high-quality predictions.
The model also outperformed on consistency when predicting peak splitting patterns and J-coupling values, two features that chemists rely on heavily to distinguish between similar molecular structures.
