AbstractNafion membranes neutralized with Ni2+have been examined by extended x‐ray absorption fine‐structure (EXAFS) and x‐ray absorption near‐edge‐structure (XANES) spectroscopy. The results indicate that in both the dry and water‐soaked membranes, the nickel is in an octahedral site with six oxygen atoms as nearest neighbors. The degree of disorder in the NiO distance is comparable to that in ionic crystals in both the dry and hydrated materials. A contribution from a second shell of neighbors is very weak in the dry samples but, surprisingly, this contribution is strongly accentuated in the hydrated membranes. The data indicate that this contribution is due to neighboring Ni2+cations. Thus the water absorption seems to enhance the local ordering of the cation environment. The local structure does not depend strongly on the concentration of ionic groups in