IR Spectroscopy Set #1

Aromatic C-C (IR Spectroscopy)

Two peaks usually in the range of 1500−1600 cm⁻¹

C=C (IR Spectroscopy)

~1650 cm⁻¹

C=O (IR Spectroscopy)

~1710 cm⁻¹

C=O (ester) (IR Spectroscopy)

~1735 cm⁻¹

C≡C (IR Spectroscopy)

~2100-2300 cm⁻¹

C≡N (IR Spectroscopy)

~2100-2300 cm⁻¹

C-H (aldehyde) (IR Spectroscopy)

Two peaks at 2710 cm⁻¹ and 2810 cm⁻¹

sp³ C-H (IR Spectroscopy)

Just to the right of 3000 cm⁻¹, 2900

sp² C-H (IR Spectroscopy)

Just to the left of 3000 cm⁻, 3100¹

sp C-H (IR Spectroscopy)

~3300 cm⁻¹

N-H (IR Spectroscopy)

~3300 cm⁻¹ (one peak for −NH, two peaks for −NH₂)

O-H (alcohol) (IR Spectroscopy)

~3400 cm⁻¹ (a broad, smooth peak)

O-H (acid) (IR Spectroscopy)

~2500−3500 cm⁻¹ (a very broad, ugly peak, not smooth)

Fingerprint region (IR Spectroscopy)

0−1400 cm⁻¹, unreliable so ignore, contains C-C, C-O and C-N