Organic Chemistry (IR Spectroscopy)

Alkane

* Just to the right of 3000 cm⁻¹ (C-C)

Alkene

* Just to the left of 3000 cm⁻¹

* Weak 1660 cm⁻¹ (C=C)

Alkyne

* Left of 3300 cm⁻¹

* Right of 2200 cm⁻¹ (C≡C) Medium

Benzene

* Left of 3000 cm⁻¹

* Two peaks usually in the range of 1500−1600 cm⁻¹ (C=C)

Ether

* Just to the right of 3000 cm⁻¹ (C-C)

* 1100-1200 cm⁻¹ (C-O ) Strong

Alcohol

* ~3400 cm⁻¹ (a broad, smooth peak)

* Just to the right of 3000 cm⁻¹ (C-C)

* absence (C=O) 1750 cm⁻¹

Carboxylic Acid

* ugly 2500-3500 (3300)

* Just to the right of 3000 cm⁻¹ (C-C)

* strong, narrow C=O 1750 cm⁻¹

Aldehyde

* C=O 1750

* Just to the right of 3000 cm⁻¹ (C-C)

* Two peaks at 2710 cm⁻¹ and 2810 cm⁻¹

Ester

* C=O 1750

* Just to the right of 3000 cm⁻¹ (C-C)

* C-O 1150

Ketone

* C=O 1750

* Just to the right of 3000 cm⁻¹ (C-C)

Amide

* C=O 1750

* Just to the right of 3000 cm⁻¹ (C-C)

* ~3300 cm⁻¹ (one peak for −NH, two peaks for −NH₂)

Amine

* (Primary) two peaks around 3400

* (Secondary) single peak around 3400

* Just to the right of 3000 cm⁻¹ (C-C)