The fine structures of ionic domains in the fluorine-containing copper (II) ionomers were examined by the Extended X-ray Absorption Fine-Structure (EXAFS) and Electron Spin Resonance (ESR). The results indicate that there are two basic coordination structure units in the ionomers. The first is a square planar coordination structure of Cu2+ ion with oxygen atoms which come from two carboxylate groups. The coordination number of Cu2+ is four and the bond distance of Cu2+-O is about 1.96A. The second is a binuclear coordination structure of Cu2+-Cu2+ ionc pairs with eight oxygen atoms which come from four carboxylate groups. In this structure

the coordination number of lst coordination shell is four and the bond distance fo Cu2+-O is about 1.96A. The 2nd shell is coordination of Cu2+-Cu2+ and the bond dis-tance of Cu2+-Cu2+ is about 2.64A.