🟣 This is Higher Level (HL) content.
🔑 Simpler Than ¹H NMR
Number of peaks = number of unique carbon environments. No splitting (signals are decoupled). No integration (peak height ≠ number of carbons).
¹³C Chemical Shift Ranges
| Environment | δ / ppm |
|---|---|
| C–C (alkyl) | 5–40 |
| C–O (alcohol/ether) | 50–90 |
| C=C (alkene/aromatic) | 110–160 |
| C=O (carbonyl) | 160–220 |
📐 Worked Example. Propanone
CH₃COCH₃ has 2 carbon environments: the two equivalent CH₃ groups (one peak ~30 ppm) and the C=O (one peak ~205 ppm). So the spectrum shows 2 peaks.