Infrared spectroscopy correlation table

An infrared spectroscopy correlation table (or table of infrared absorption frequencies) is a list of absorption peaks and frequencies, typically reported in wavenumber, for common types of molecular bonds and functional groups.[1][2] In physical and analytical chemistry, infrared spectroscopy (IR spectroscopy) is a technique used to identify chemical compounds based on the way infrared radiation is absorbed by the compound.

Further information: Infrared spectroscopy

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.[3]

Group frequencies

Tables of vibrational transitions of stable[4] and transient molecules[5] are also available.

Bond Type of bond Specific type of bond Absorption peak (cm−1) Appearance
C─H alkyl methyl 1260 strong
1380 weak
2870 medium to strong
2960 medium to strong
methylene 1470 strong
2850 medium to strong
2925 medium to strong
methine 2890 weak
vinyl C═CH2 900 strong
2975 medium
3080 medium
C═CH 3020 medium
monosubstituted alkenes 900 strong
990 strong
cis-disubstituted alkenes 670–700 strong
trans-disubstituted alkenes 965 strong
trisubstituted alkenes 800–840 strong to medium
aromatic benzene/sub. benzene 3070 weak
monosubstituted benzene 700–750 strong
690–710 strong
ortho-disub. benzene 750 strong
meta-disub. benzene 750–800 strong
860–900 strong
para-disub. benzene 800–860 strong
alkynes any 3300 medium
aldehydes any 2720 medium
2820
C═C acyclic C═C monosub. alkenes 1645 medium
1,1-disub. alkenes 1655 medium
cis-1,2-disub. alkenes 1660 medium
trans-1,2-disub. alkenes 1675 medium
trisub., tetrasub. alkenes 1670 weak
conjugated C═C dienes 1600 strong
1650 strong
with benzene ring 1625 strong
with C═O 1600 strong
C═C (both sp2) any 1640–1680 medium
aromatic C═C any 1450 weak to strong (usually 3 or 4)
1500
1580
1600
C≡C terminal alkynes 2100–2140 weak
disubst. alkynes 2190–2260 very weak (often indistinguishable)
C=O aldehyde/ketone saturated aliph./cyclic 6-membered 1720
α,β-unsaturated 1685
aromatic ketones 1685
cyclic 5-membered 1750
cyclic 4-membered 1775
aldehydes 1725 influenced by conjugation (as with ketones)
carboxylic acids/derivates saturated carboxylic acids 1710
unsat./aromatic carb. acids 1680–1690
esters and lactones 1735 influenced by conjugation and ring size (as with ketones)
anhydrides 1760
1820
acyl halides 1800
amides 1650 associated amides
carboxylates (salts) 1550–1610
amino acid zwitterions 1550–1610
O─H alcohols, phenols low concentration 3610–3670
high concentration 3200–3400 broad
carboxylic acids low concentration 3500–3560
high concentration 3000 broad
N─H primary amines any 3400–3500 strong
1560–1640 strong
secondary amines any >3000 weak to medium
ammonium ions any 2400–3200 multiple broad peaks
C─O alcohols primary 1040–1060 strong, broad
secondary ~1100 strong
tertiary 1150–1200 medium
phenols any 1200
ethers aliphatic 1120
aromatic 1220–1260
carboxylic acids any 1250–1300
esters any 1100–1300 two bands (distinct from ketones, which do not possess a C─O bond)
C─N aliphatic amines any 1020–1220 often overlapped
C═N any 1615–1700 similar conjugation effects to C═O
C≡N (nitriles) unconjugated 2250 medium
conjugated 2230 medium
R─N─C (isocyanides) any 2165–2110
R─N═C═S (isothiocyanates) any 2140–1990
C─X fluoroalkanes ordinary 1000–1100
trifluromethyl 1100–1200 two strong, broad bands
chloroalkanes any 540–760 weak to medium
bromoalkanes any 500–600 medium to strong
iodoalkanes any 500 medium to strong
N─O nitro compounds aliphatic 1540 stronger
1380 weaker
aromatic 1520 lower if conjugated
1350
P─C Organophosphorus compound aromatic 1440-1460 medium
P─O phosphorus oxide bonded 1195-1250 strong
free 1250-1300 strong
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See also

References
  1. George Socrates (12 April 2004). Infrared and Raman Characteristic Group Frequencies: Tables and Charts. John Wiley & Sons. pp. 18–. ISBN 978-0-470-09307-8. Retrieved 5 December 2012.
  2. Peter Larkin (25 May 2011). Infrared and Raman Spectroscopy; Principles and Spectral Interpretation. Elsevier. ISBN 978-0-12-386984-5. Retrieved 5 December 2012.
  3. Kazuo Nakamoto (16 January 2009). Infrared and Raman Spectra of Inorganic and Coordination Compounds, Applications in Coordination, Organometallic, and Bioinorganic Chemistry. John Wiley & Sons. pp. 9–. ISBN 978-0-470-40587-1. Retrieved 13 December 2012.
  4. NSRDS-NBS: National Standard Reference Data Series, National Bureau of Standards (PDF). U.S. Government Printing Office. June 1972. Retrieved 13 December 2012.
  5. Jacox, Marilyn E. (2003). "Vibrational and Electronic Energy Levels of Polyatomic Transient Molecules. Supplement B". Journal of Physical and Chemical Reference Data. 32 (1): 1. Bibcode:2003JPCRD..32....1J. doi:10.1063/1.1497629. ISSN 0047-2689.
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