Common IR/NMR Spectroscopy Values

IHD / Degrees of Unsaturation

Aromatic C-C

1500-1600 cm^-1

C=C

1550-1650 cm^-1

C=O

~1700 cm^-1; Very sharp peak

Alkyne (C triple C)

2100-2260 cm^-1; Medium/weak intensity peak

Nitrile (C triple N)

2200-2260 cm^-1; Sharp peak

sp³ C-H

2850-3000 cm^-1

sp² C-H

3000-3100 cm^-1; Medium peak

sp C-H

~3300 cm^-1

Alcohol (-OH)

3200-3500 cm^-1; Broad, smooth peak

Amide (NH/NH₂)

3300-3500 cm^-1; Very sharp, teeth-like peaks; Number of peaks relates to substitution of amide. i.e. two peaks = NH₂

¹H NMR; C-H

0.5-1.5 ppm

¹H NMR; Alkyne

2.0-3.0 ppm

¹H NMR; R-OH

1.0-5.0 ppm; Position changes based on H-bonding

¹H NMR; X-CH (X=F, Cl, Br, I)

3.0-5.0 ppm

¹H NMR; Ether (R-O-CH)

3.2-4.0 ppm

¹H NMR; Aromatic -H

6.5-8.5 ppm

¹H NMR; Aldehyde (R-CHO)

9.0-10.0 ppm; Always a singlet (no neighboring H’s)

¹H NMR; Carboxylic Acid (R-COOH)

10.0-13.0 ppm

¹³C NMR; Methyl (CH₃)

10-20 ppm; sp₂ and sp are slightly higher, respectively

¹³C NMR; C-X (X=halogen)

50-90 ppm

¹³C NMR; C-OR / C-OH

50-80 ppm

¹³C NMR; Alkyne (C triple C)

70-90 ppm

¹³C NMR; Alkene (C=C)

110-150 ppm

¹³C NMR; Aromatic C

110-160 ppm

¹³C NMR; Nitrile (C triple N)

110-130 ppm

¹³C NMR; Amide (R-CO-N-R₂)

150-165 ppm

¹³C NMR; Ester (R-CO-OR)

155-180 ppm

¹³C NMR; Carboxylic Acid (R-COOH)

165-190 ppm

¹³C NMR; Aldehyde (R-CHO)

190-200 ppm

¹³C NMR; Ketone (R₂-C=O)

200-220 ppm