Polyaniline Sn(IV) phosphate, an 'organic-inorganic' composite material, was synthesized via sol-gel mixing of an electrically conducting organic polymer polyaniline into the matrices of inorganic precipitate of Sn(IV) phosphate. This material was used as a cation-exchanger. The physico-chemical properties of the material were determined using AAS, CHN elemental analysis, ICP-MS, UV-VIS spectrophotometry, FTIR, TGA-DTA, XRD, and SEM studies. Ion-exchange capacity, chemical stability, thermal stability and distribution behavior were also carried out to understand the cation-exchange behavior of the material. On the basis of distribution studies, the material was found to be highly selective for Pb(II). Its selectivity was examined by achieving some important binary separations like Pb(II)-Mg(II), Pb(II)-Sr(II), Pb(II)-Zn(II), and Pb(II)-Fe(III) on its column. This material possessed DC electrical conductivity in the semi-conducting range, i.e. 10(-5)-10(-3) S cm(-1). The stability in terms of DC electrical conductivity retention was also studied in an oxidative environment by two slightly different techniques viz. isothermal and cyclic techniques. The DC electrical conductivity of composite material was found stable upto 110 degrees C under ambient conditions. (c) 2006 Elsevier B.V. All rights reserved.