Bond
| Type of bond
| Specific type of bond
| Absorption range and intensity
|
C-H
| alkyl
| methyl
| 1380 cm-1 (weak), 1260 cm-1 (strong) and 2870, 2960 cm-1 (both strong to medium)
|
|
| methylene
| 1470 cm-1 (strong) and 2850, 2925 cm-1 (both strong to medium)
|
|
| methine
| 2890 cm-1 (weak)
|
| vinyl
| C=CH2
| 900 cm-1 (strong) and 2975, 3080 cm-1 (medium)
|
|
| C=CH
| 3020 cm-1 (medium)
|
|
| monosubstituted alkenes
| 900, 990 cm-1 (both strong)
|
|
| cis-disubstituted alkenes
| 670-700 cm-1 (strong)
|
|
| trans-disubstituted alkenes
| 965 cm-1 (strong)
|
|
| trisubstituted alkenes
| 800-840 cm-1 (strong to medium)
|
| aromatic
| benzene/sub. benzene
| 3070 cm-1 (weak)
|
|
| monosubstituted benzene
| 700-750 cm-1 (strong) and 700±10 cm-1 (strong)
|
|
| ortho-disub. benzene
| 750 cm-1 (strong)
|
|
| meta-disub. benzene
| 750-800 cm-1 (strong) and 860-900 cm-1 (strong)
|
|
| para-disub. benzene
| 800-860 cm-1 (strong)
|
| alkynes
|
| 3300 cm-1 (medium)
|
| aldehydes
|
| 2720, 2820 cm-1 (medium)
|
C-C
| acyclic C-C
| monosub. alkenes
| 1645 cm-1 (medium)
|
|
| 1,1-disub. alkenes
| 1655 cm-1 (medium)
|
|
| cis-1,2-disub. alkenes
| 1660 cm-1 (medium)
|
|
| trans-1,2-disub. alkenes
| 1675 cm-1 (medium)
|
|
| trisub., tetrasub. alkenes
| 1670 cm-1 (weak)
|
| conjugated C-C
| dienes
| 1600, 1650 cm-1 (strong)
|
|
| with benzene ring
| 1625 cm-1 (strong)
|
|
| with C=O
| 1600 cm-1 (strong)
|
| C=C (both sp2)
|
| 1640-1680 cm-1 (medium)
|
| aromatic C=C
|
| 1450, 1500, 1580, 1600 cm-1 (strong to weak) — usually 3 or 4
|
| C≡C
| terminal alkynes
| 2100-2140 cm-1 (weak)
|
|
| disubst. alkynes
| 2190-2260 cm-1 (very weak, sometimes not visible)
|
C=O
| aldehyde/ketone
| saturated aliph./cyclic 6-membered
| 1720 cm-1
|
|
| α,β-unsaturated
| 1685 cm-1 (goes for aromatic ketones as well)
|
|
| cyclic 5-membered
| 1750 cm-1
|
|
| cyclic 4-membered
| 1775 cm-1
|
|
| aldehydes
| 1725 cm-1 (influence of conjugation like with ketones)
|
| carboxylic acids/derivates
| saturated carboxylic acids
| 1710 cm-1
|
|
| unsat./aromatic carb. acids
| 1680-1690 cm-1
|
|
| esters and lactones
| 1735 cm-1 (influence of conjugation and ring size like with ketones)
|
|
| anhydrides
| 1760 and 1820 cm-1 (both!)
|
|
| Acyl Halides
| 1800 cm-1
|
|
| amides
| 1650 cm-1 (associated amides)
|
|
| carboxylates (salts)
| 1550-1610 cm-1 (goes for aminoacid zwitterions as well)
|
O-H
| alcohols, phenols
|
| 3610-3670 cm-1 (concentrating samples broadens the band and moves it to 3200-3400 cm-1)
|
| carboxylic acids
|
| 3500-3560 cm-1 (concentrating samples broadens the band and moves it to 3000 cm-1)
|
N-H
| primary amines
|
| doublet between 3400-3500 cm-1 and 1560-1640 cm-1 (strong)
|
| secondary amines
|
| above 3000 cm-1 (medium to weak)
|
| ammonium ions
|
| broad bands with multiple peaks between 2400-3200 cm-1
|
C-O
| alcohols
| primary
| 1050±10 cm-1 (strong, broad)
|
|
| secondary
| around 1100 cm-1 (strong)
|
|
| tertiary
| 1150-1200 cm-1 (medium)
|
| phenols
|
| 1200 cm-1
|
| ethers
| aliphatic
| 1120 cm-1
|
|
| aromatic
| 1220-1260 cm-1
|
| carboxylic acids
|
| 1250-1300 cm-1
|
| esters
|
| 1100-1300 cm-1 (two bands - distinction to ketones, which do not possess C-O!)
|
C-N
| aliphatic amines
|
| 1020-1220 cm-1 (often overlapped)
|
| C=N
|
| 1615-1700 cm-1 (similar conjugation effects to C=O)
|
| nitriles (triple C-N bond)
|
| 2210-2260 cm-1 (unconjugated 2250, conjugated 2230 cm-1) (medium)
|
| isonitriles (R-N-C bond)
|
| 2165-2110 cm-1 (2140 - 1990 cm-1 for R-N=C=S)
|
C-X (X=F, Cl, Br, I)
| fluoroalkanes
| ordinary
| 1000-1100 cm-1
|
|
| trifluromethyl
| two strong, broad bands between 1100-1200 cm-1
|
| chloroalkanes
|
| 540-760 cm-1 (medium to weak)
|
| bromoalkanes
|
| 500-600 cm-1 (strong to medium)
|
| iodoalkanes
|
| 500 cm-1 (strong to medium)
|
N-O
| nitro compounds
| aliphatic
| 1540 cm-1 (stronger band) and 1380 cm-1 (weaker band) - (Both are always found)
|
|
| aromatic
| 1520, 1350 cm-1 (conjugation usually lowers the wave number)
|