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How to predict a 13C NMR spectrum

Select the structure and choose Object › Chemistry › Predict 13C NMR, or switch the Predicted NMR window to its 13C tab. Each carbon gets a predicted shift, a 90% range, its type (CH3, CH2, CH or C) and its environment.

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Steps

  1. Select the structure with Select (V).

  2. Choose Object › Chemistry › Predict 13C NMR. If the Predicted NMR window is already open, click its ¹³C tab.

  3. The spectrum shows one line per carbon environment, at 101 MHz for carbon. The table lists:

    • δ (ppm), the predicted shift, and its 90% range;
    • Type: CH3, CH2, CH or C, which is what a DEPT experiment would tell you;
    • Environment, such as C=O or OCH₂.

    The 13C tab for ethyl acetate: four lines at 171.2, 60.4, 21.0 and 14.2 ppm with their types and environments.The 13C tab for ethyl acetate: four lines at 171.2, 60.4, 21.0 and 14.2 ppm with their types and environments.

Prediction

Predicted by Athanor Resonantia, not measured, with a typical error of 0.7 ppm on held-out data. The CH3, CH2, CH and C types come from the drawn structure, not from the prediction. See How accurate predicted NMR shifts are.

NMR and spectraHow accurate predicted NMR shifts areOn data the model never saw, predicted 1H shifts are typically within 0.08 ppm and 13C shifts within 0.7 ppm. Each shift comes with a 90% range. Multiplicities, J values and carbon types are worked out from the structure, not predicted.NMR and spectraHow to copy NMR data as journal textIn the Predicted NMR window, press Copy as journal text. The data is copied as one line in journal style, for example "¹H NMR (400 MHz, CDCl3, predicted) δ 4.11 (q, J = 7.0 Hz, 2H), ...". Paste it with Ctrl+V.

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Last updated Nov 12, 2026