IR Spectra

alkane

alkane

3000 - 2800 cm⁻¹

methylene

~1450 cm⁻¹

methyl

~1370 cm⁻¹

isopropyl

approximately equal intensity doublet at ~1360 and ~1380 cm⁻¹

t-butyl

unsymmetrical doublet at ~1360 and ~1390 cm⁻¹

alkene

3100 - 3000 cm⁻¹
weak confirming peak at 1660 - 1600 cm⁻¹

terminal alkyne

~3300 cm⁻¹
weak confirming peak at ~2150 cm⁻¹

aromatic ring

just left of 3000 cm⁻¹
possible confirming peaks at ~1500 and ~1600 cm⁻¹

O-H stretch

broad peak at 3600 - 3200 cm⁻¹

C-O stretch

1250 - 1050 cm⁻¹

1° alcohol

broad peak at 3600 - 3200 cm⁻¹
C-O peak at ~1050 cm⁻¹

2° alcohol

broad peak at 3600 - 3200 cm⁻¹
C-O peak at ~1125 cm⁻¹

3° alcohol

broad peak at 3600 - 3200 cm⁻¹
C-O peak at ~1200 cm⁻¹

phenol

broad peak at 3600 - 3200 cm⁻¹
C-O peak at ~1500 and ~1600 cm⁻¹

aliphatic ether

C-O peak at 1280 - 1200 cm⁻¹

aryl ether

C-O peak at 1080 - 1020 cm⁻¹

C=O stretch for ketones and aldehydes

1780 - 1660 cm⁻¹

aldehyde

strong peak at 1780 - 1660 cm⁻¹
two weak peaks ~2820 and ~2700 cm⁻¹

ketone

strong peak at 1780 - 1660 cm⁻¹

C=O stretch for carboxylic acid derivatives

1840 - 1630 cm⁻¹

acid chloride

peak at slightly higher frequencies than other CADs

acid anhydride

two peaks at 1840 - 1740 cm⁻¹
C-O peak at ~1100 cm⁻¹

aliphatic ester

peak at ~1740 cm⁻¹
C-O peak at 1300 - 1100 cm⁻¹

aryl ester

peak at ~1720 cm⁻¹
C-O peak at 1300 - 1100 cm⁻¹

amide

peak at 1690 - 1630 cm⁻¹
broad peak(s) at 3500 - 3300 cm⁻¹

nitrile

moderate to weak peak at 2300 - 2200 cm⁻¹

1° amine

two peaks at 3500 - 3300 cm⁻¹
weak C-N peak at 1350 - 1000 cm⁻¹

2° amine

one peak at 3500 - 3300 cm⁻¹
weak C-N peak at 1350 - 1000 cm⁻¹

3° amine

weak C-N peak at 1350 - 1000 cm⁻¹

nitro

two strong peaks at 1600 - 1500 cm⁻¹ and 1390 - 1300 cm⁻¹