Octet

Octet / IR Absorption Table

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.

IR Absorption Table details

Functional Group

Ester C=O

Wavenumber Range

1735-1750

Intensity

strong

Appearance

Sharp

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IR Absorption Table

Related Content

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.

Study guides

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Free, in-depth guides that put this material in context.

IR spectroscopy basicsIdentify functional groupsReading NMR basicsAll guides