Selenols

thumb|Selenocysteine ball and stick model spinning Selenocysteine (symbol Sec or U, in older publications also as Se-Cys) is the 21st proteinogenic amino acid. Selenoproteins contain selenocysteine residues. Selenocysteine is an analogue of the more common cysteine with selenium in place of the sulfur.

Benzeneselenol, also known as selenophenol, is the organoselenium compound with the chemical formula , often abbreviated PhSeH. It is the selenium analog of phenol. This colourless, malodorous compound is a reagent in organic synthesis.

thumb|right|upright=0.5|The structure of a generic selenol

Methaneselenol is the organoselenium compound with the formula . It is the simplest selenol. A colorless, poisonous gas, it is notorious for its foul, putrid odor.