Abstract: Anew inorganic ion exchanger—stannic selenopyrophosphate has beensynthesized. The studies on its chemical composition, ion exchange capacity, pHtitration,thermal and chemical stability,distribution coefficients of thirty seven metal ions, IR, Raman spectrometry and X-ray analysis show that it is a polyfunctional cation exchanger possessing high ion exchange capacity and good chemical stability. It has a high affinity for Ag(Ⅰ), Pb( Ⅱ ), Ba( Ⅱ ), Bi( Ⅲ ) and Zr(Ⅳ).An empirical formula representing the relationship of ion exchange capacity of alkali and alkaline earth metal ions with bare radii and charges has been proposed. And a possible chemical formula of stannic selenopyrophosphate has also been inferred.