This paper describes the synthesis of phosphonic acids (R–S–(CH2) 2–PO (OH) 2) containing a perfluoroalkylated chain (R= C6F13–(CH2) 2, C8F17–(CH2) 2) or an alkyl group (R= C12H25, C18H37). These compounds, obtained in excellent yield by telomerization of vinyl phosphonic acid in the presence of alkylated or perfluorinated mercaptans used as transfer agents, were characterized by 1H, 19F and 31P nuclear ...