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Some characteristic absorption frequencies in IR spectroscopy

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Bond type

Frequency (cm-1)

C-H alkane

2950 – 2850

C-H alkene

3080 – 3020

C-H aldehyde

~2900

C-H alkyne

~3300

alkyne triple bond

2250 – 2100 (s)

alkene double bond

1680 - 1620 (s)

carbonyl, ketone

1725 – 1700 (s)

carbonyl, aldehyde

1740 – 1720 (s)

carbonyl, ester

1750 – 1730 (s)

carbonyl, acid

1725 – 1700 (s)

carbonyl, amide

1690 – 1650 (s)

O-H, alcohol

3600 – 3200 (s, broad)

O-H, acid

3000 – 2500 (s, broad)

C-O, alcohol, ester, ether

1300 - 1000

 

s = strong absorbance

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Contributors

  • Organic Chemistry With a Biological EmphasisTim Soderberg (University of Minnesota, Morris)