Structural Characterization of Intercalated C2Fx Compounds Using XAFS Polarization Dependencies

Orientation dependencies of FeK, BrK EXAFS and XANES spectra have been measured for intercalated compounds of the composition CZF, *yA (X = 1 . A= Brz, BrF3, FeBr3, Fe(AA)3, FeCl3) synthesized by dityusion from solutions. An approach has been developed which allows determination of the ranges of the orientation angles of T-shaped BrF3 molecules tiom XANES spectra. The values of the orientation angles of BrF3 molecules were determined by simultaneously analyzing EX4FS and XANES data. It was found that heating leads to the formation in the intercalated compound of lens-like regions containing oriented BrF3 molecules. The orientation and geometry of Brz moleculas in the studied compounds were shorn to be substantially different Gom those in graphite intercalation compounds. The intercalation was shown to lead to deformation of the Fe(AA)3 molecule while the FeCb molecules form dii~ers.