NMR Chemical
Shift Predictor
Predict expected ¹H NMR chemical shifts using functional groups and molecular environments.
Live prediction · Alcohol
δ 3.5–4.2 ppm
Workspace
Choose an environment — the prediction updates instantly.
Predicted range
δ 3.5–4.2 ppm
Typical range · Midpoint ≈ 3.84 ppm · Alcohol
Typical proton adjacent to oxygen.
Prediction confidence is high because this environment closely matches well-established experimental proton NMR ranges.
Visualization
DeshieldingWhy this result
- 01The proton is in a alcohol environment. Textbook reference ranges place the characteristic proton(s) near δ 3.3–4.0 ppm.
- 02The proton is attached to (or near) carbon adjacent to oxygen. Oxygen withdraws electron density through the inductive effect. This deshields the proton, causing a downfield shift.
- 03Hydrogen bonding reduces electron density at the proton (especially OH/NH), shifting the signal downfield and often broadening it.
- 04Neighboring C withdraw electron density through the inductive effect, deshielding the observed proton.
- 05Weak H-bonding partially deshields the proton (especially exchangeable OH/NH).
- 06Typical adjusted range: δ 3.5–4.2 ppm.
Rule adjustments
Why not another shift?
Why not ~1.2 ppm?
That region is typical of remote alkyl protons. This environment is not a simple shielded alkane C–H.
Why not ~2.2 ppm?
≈2.2 ppm usually means α-to-carbonyl, benzylic, or similar mildly deshielded alkyl protons — not this motif.
Why not ~7.2 ppm?
≈7.2 ppm typically requires aromatic ring current deshielding (or CHCl₃). No arene-like environment is selected.
Chemical shift scale
0 → 12 ppm · highlighted band = current prediction
Learn & understand
Concepts, side-by-side ranges, and the reference table
Shielding
Electron density around a nucleus reduces the effective magnetic field it feels.
- In NMR, nuclei are studied in a strong external magnetic field B₀.
- Surrounding electrons generate a small opposing field — this shields the nucleus.
- More shielding → resonance at lower frequency → smaller chemical shift (upfield, right on conventional plots).
- Alkyl protons far from electronegative atoms are relatively shielded (~0.8–1.5 ppm).
Continue your NMR workflow
A path from impurity check → prediction → assignment
- 1
NMR Impurity Solver
CompletedIdentify common solvent impurities before assigning compound peaks.
- 2
NMR Chemical Shift Predictor
You are herePredict unknown proton environments after removing solvent impurities.
- 3
NMR Splitting Pattern Simulator
AvailableUnderstand why peaks split into doublets, triplets and multiplets.
- 4
Peak Assignment Assistant
AvailableAssign ¹H peaks to atoms with shift, multiplicity, and structure.
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Frequently asked questions
Is this an AI chemical shift predictor?
No. It is a deterministic reference engine based on established ¹H NMR teaching ranges and additive environmental corrections (inductive effects, aromaticity, H-bonding, conjugation, EDG/EWG).
How accurate are the predicted ranges?
Ranges are designed for undergraduate/early research education and spectrum triage. Real spectra also depend on solvent, concentration, temperature, and stereochemistry. Use confidence + explanations as guidance, not a substitute for measured NMR.
Why do alcohol OH and amine NH predictions have lower confidence?
Exchangeable protons are highly solvent- and concentration-dependent and often disappear after D₂O exchange. Their chemical shifts can span several ppm.
Can I predict ¹³C chemical shifts?
Not in this tool yet. The rule modules under src/lib/chemistry/nmr are structured so a Carbon-13 Predictor can reuse the same architecture.
Does my data leave the browser?
No. Everything runs client-side. There is no backend API and no database for this tool.
What references are the ranges based on?
Classic organic spectroscopy teaching tables (Silverstein-style / Pavia-style ¹H windows) and common laboratory references used in undergraduate NMR courses.