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Infrared spectroscopy correlation table



Further information: Infrared spectroscopy
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)

The absorptions in this range do not apply only to bonds in organic molecules. IR spectroscopy is useful when it comes to analysis of inorganic compounds (such as metal complexes or fluoromanganates) as well.

 
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Infrared_spectroscopy_correlation_table". A list of authors is available in Wikipedia.
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