Thiol

The most striking characteristic of thiols is their appalling odor. Skunk scent, for instance, is caused primarily by the simple thiols 3-methyl-1-butanethiol and 2-butene-1-thiol. Volatile thiols such as ethanethiol are also added to natural gas and liquefied propane to serve as an easily detectable warning in case of leaks.

— Thiol

Thiols can be oxidized by Br to yield disulfides (RSSR′). The reaction is easily reversed, and a disulfide can be reduced back to a thiol by treatment with zinc and acid.

— Thiol