2. Chemical Shift (δ, ppm)
Determines the electronic environment of the proton.
Typical ranges (approximate values):
0–3 ppm: Alkyl (CH₃, CH₂, CH)
2–3 ppm: Protons near electronegative groups (e.g., -C≡C-H, -CO-CH₃)
3–5 ppm: Protons near oxygen or halogens (-O-CH₃, -Cl-CH₃)
5–7 ppm: Alkene protons (-C=CH)
6–9 ppm: Aromatic protons (benzene ring)
9–10 ppm: Aldehyde (-CHO)
10–12 ppm: Carboxylic acid (-COOH)
