One new and three known derivatives of dibutylphosphonic acid, namely, the α,α′-bis(dibutylphosphonato{)-l,3-xylene and bis(dibutylphosphonato)alkanes, commonly known as the tetrabutyl 1,3-xylylenediphosphonate (TBmXDP) and tetrabutyl alkylenediphosphonates (TBADP), respectively, were synthesized for use in the solvent extraction of precious metals. From 0·1M (1M =1 mol dm−3) NaCl solution at pH 3, these bifunctional reagents substantially extract Au(III), Cu(II) and Sm(III) in 1,2-dichloroethane (DCE), where the extent of extraction as well as the extraction selectivity is governed by the length of the hydrocarbon chain joining the two P=0 groups in the diphosphonate molecule. Au(III)extraction from hydrochloric acid medium was studied in detail by using tetrabutyl 1,3-xylyienediphosphonate because of its superior extraction properties. In hydrochloric acid solutions (0·1 to 5·0 M), the extraction of Au(III) proceeds through formation of a 1:1 solvating complex, TBmXDP-HAuCl4and the equilibrium constant of the extraction reaction (Kex) varies with aqueous HCl concentration. The monofunctional P=0 containing ligand, tributyl phosphate (TBP) also follows similar stoichiometry in its extraction of Au(III); but with much lower values of Kex. On the basis of solubility and phase characteristics of TBmXDP-HAuCl4system, a mixed diluent is proposed for the recovery of gold using this reagent The selectivity of extraction, stripping and extraction kinetics were evaluated in relation to the recovery of the metal from acidic waste solutions and the data are compared with those of TBP.