Question

Do halogens appear in the IR spectrum? For example, bromine attached to a benzene molecule, where would the bromine appear on the IR spectra?

Answer 1

The `"C-Br"` stretch usually appears as an absorption between `"600 cm"^"-1"` and `"500 cm"^"-1"`.

Explanation:

For example, the IR spectrum of bromoethane is

(From the NIST WebBook - National Institute of Standards and Technology)

The absorption at `"560 cm"^"-1"` is the `"C-Br"` stretching vibration.