An EXAFS study of the structure of rubidium polyethyleneoxide salt complexes
Abstract EXAFS measurements on the Rb K edge of RbSCN(PEO) x and RbI(PEO) x (x=4,88) for temperatures in the range 80K to 453K have been performed to gain information about the local structural environment of Rb in these complexes. It has been shown that Rb adopts well-defined sites of four co-ordination with ether oxygens, the actual configuration being anion-dependent. For the iodide samples, there are two short and two long Rb-O bonds with the iodide situated outside the first co-ordination shell at 3.7A. The thiocyanate complexes have a single shell of oxygen neighbours and it is suggested that the N atom of the thiocyanate group is also located within the first shell. No anomalous change in thermal motion, nor any change in cation site geometry is observed on heating.