Nitro compound infrared spectra

1-nitrohexane

Nitrobenzene

Aliphatic NO₂ stretch: Strong asymmetric at 1600-1530 and medium symmetric at 1390-1300.

Conjugated NO₂ stretch: Strong asymmetric at 1550-1490 and strong symmetric at 1355-1315.

These bands may partially overlap the C=C region, but are usually easy to distinguish.