Perfluorinated carboxylic acids (PFCAs), or perfluorocarboxylic acids are compounds of the formula C_nF_(2n+1)CO₂H. The simplest example is trifluoroacetic acid. These compounds are organofluorine analogues of ordinary carboxylic acids, but they are stronger by several pK_a units and they exhibit great hydrophobic character. Perfluorinated dicarboxylic acids are also known, e.g. C₂F₄(CO₂H)₂.