IR spectroscopy common absorptions

Ch 12

Aromatic C-C

1500-1600 cm^-1

(2 peaks)

C=C

~1650 cm^-1

C=O

~1710 cm^-1

Esters

~1735 cm^-1

C≡C

~2100-2300 cm^-1

C≡N

~2100-2300 cm^-1

C-H (aldehyde)

1 peak @ 2710 cm^-1 and 1 @ 2810 cm^-1

sp³ C-H

right of 3000 cm^-1

sp² C-H (alkenyl)

left of 3000 cm^-1

sp C-H (alkyl)

~3300 cm-1

-NH-

~3300 cm^-1

1 peak

-NH₂

~3300 cm^-1

2 peaks

O-H (alcohol)

~3400 cm^-1

broad, smooth

O-H (acid)

~2500-3500 cm^-1

broad, ugly, not smooth

Fingerprint region

~500-1500 cm^-1

Ketone

1750-1680 cm