Octet / Collection
IR
Infrared absorption ranges by functional group, with band intensity and shape.
1-28 of 28 records
All IR
Infrared absorption ranges by functional group, with band intensity and shape.
Alcohol O-H
Alcohol O-H absorbs in the IR at 3200-3600 cm⁻¹. Intensity: strong, band shape: Broad. Use this range to identify the group from an IR spectrum.
Carboxylic acid O-H
Carboxylic acid O-H absorbs in the IR at 2500-3300 cm⁻¹. Intensity: strong, band shape: Very broad, often overlaps C-H. Use this range to identify the group from an IR spectrum.
Phenol O-H
Phenol O-H absorbs in the IR at 3200-3600 cm⁻¹. Intensity: strong, band shape: Broad. Use this range to identify the group from an IR spectrum.
Primary amine N-H
Primary amine N-H absorbs in the IR at 3300-3500 cm⁻¹. Intensity: medium, band shape: Two peaks (symmetric/asymmetric). Use this range to identify the group from an IR spectrum.
Secondary amine N-H
Secondary amine N-H absorbs in the IR at 3300-3500 cm⁻¹. Intensity: medium, band shape: One peak. Use this range to identify the group from an IR spectrum.
Amide N-H
Amide N-H absorbs in the IR at 3150-3400 cm⁻¹. Intensity: medium, band shape: Broad, may have two peaks. Use this range to identify the group from an IR spectrum.
Alkane C-H (sp³)
Alkane C-H (sp³) absorbs in the IR at 2850-3000 cm⁻¹. Intensity: strong, band shape: Sharp. Use this range to identify the group from an IR spectrum.
Alkene =C-H (sp²)
Alkene =C-H (sp²) absorbs in the IR at 3000-3100 cm⁻¹. Intensity: medium, band shape: Sharp, just above 3000. Use this range to identify the group from an IR spectrum.
Alkyne ≡C-H (sp)
Alkyne ≡C-H (sp) absorbs in the IR at 3300 cm⁻¹. Intensity: strong, band shape: Sharp, narrow. Use this range to identify the group from an IR spectrum.
Aldehyde C-H
Aldehyde C-H absorbs in the IR at 2700-2850 cm⁻¹. Intensity: medium, band shape: Two peaks (Fermi doublet). Use this range to identify the group from an IR spectrum.
Aromatic C-H
Aromatic C-H absorbs in the IR at 3000-3100 cm⁻¹. Intensity: medium, band shape: Multiple peaks. Use this range to identify the group from an IR spectrum.
Alkyne C≡C
Alkyne C≡C absorbs in the IR at 2100-2260 cm⁻¹. Intensity: variable, band shape: Sharp (weak or absent if symmetric). Use this range to identify the group from an IR spectrum.
Nitrile C≡N
Nitrile C≡N absorbs in the IR at 2200-2260 cm⁻¹. Intensity: strong, band shape: Sharp, distinctive. Use this range to identify the group from an IR spectrum.
Alkene C=C
Alkene C=C absorbs in the IR at 1620-1680 cm⁻¹. Intensity: variable, band shape: Sharp (weak if symmetric). Use this range to identify the group from an IR spectrum.
Aromatic C=C
Aromatic C=C absorbs in the IR at 1450-1600 cm⁻¹. Intensity: medium, band shape: Multiple peaks. Use this range to identify the group from an IR spectrum.
Imine C=N
Imine C=N absorbs in the IR at 1640-1690 cm⁻¹. Intensity: medium, band shape: Sharp. Use this range to identify the group from an IR spectrum.
Aldehyde C=O
Aldehyde C=O absorbs in the IR at 1720-1740 cm⁻¹. Intensity: strong, band shape: Sharp. Use this range to identify the group from an IR spectrum.
Ketone C=O
Ketone C=O absorbs in the IR at 1705-1725 cm⁻¹. Intensity: strong, band shape: Sharp. Use this range to identify the group from an IR spectrum.
Carboxylic acid C=O
Carboxylic acid C=O absorbs in the IR at 1700-1725 cm⁻¹. Intensity: strong, band shape: Sharp. Use this range to identify the group from an IR spectrum.
Ester C=O
Ester C=O absorbs in the IR at 1735-1750 cm⁻¹. Intensity: strong, band shape: Sharp. Use this range to identify the group from an IR spectrum.
Amide C=O
Amide C=O absorbs in the IR at 1630-1690 cm⁻¹. Intensity: strong, band shape: Sharp (lower due to resonance). Use this range to identify the group from an IR spectrum.
Acyl halide C=O
Acyl halide C=O absorbs in the IR at 1795-1815 cm⁻¹. Intensity: strong, band shape: Sharp (highest C=O). Use this range to identify the group from an IR spectrum.
Anhydride C=O
Anhydride C=O absorbs in the IR at 1740-1840 cm⁻¹. Intensity: strong, band shape: Two peaks. Use this range to identify the group from an IR spectrum.
Conjugated C=O
Conjugated C=O absorbs in the IR at 1665-1685 cm⁻¹. Intensity: strong, band shape: Lower than unconjugated. Use this range to identify the group from an IR spectrum.
C-O (alcohols, ethers)
C-O (alcohols, ethers) absorbs in the IR at 1050-1150 cm⁻¹. Intensity: strong, band shape: Broad. Use this range to identify the group from an IR spectrum.
C-O (esters)
C-O (esters) absorbs in the IR at 1000-1300 cm⁻¹. Intensity: strong, band shape: Two peaks often. Use this range to identify the group from an IR spectrum.
Nitro N=O
Nitro N=O absorbs in the IR at 1515-1560 & 1345-1385 cm⁻¹. Intensity: strong, band shape: Two strong peaks. Use this range to identify the group from an IR spectrum.
S-H (thiol)
S-H (thiol) absorbs in the IR at 2550-2600 cm⁻¹. Intensity: weak, band shape: Sharp, distinctive. Use this range to identify the group from an IR spectrum.
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