Pentafluorophenol is the organofluorine compound (specifically a fluoroalcohol) with the formula C6F5OH.

It is a white solid that melts just above room temperature, and smells of phenol.

With a pKa of 5.5, it is one of the most acidic phenols.

Pentafluorophenol is used to prepare pentafluorophenyl esters, which are active esters useful in peptide synthesis.

[1] Pentafluorophenol is considered hazardous because of oral, dermal and inhalation toxicity and because it causes severe skin burns and eye damage.