Infrared study of group V hexafluoride fullerides

Compounds of and hexafluoride ions of group V elements (P, As, Sb) were studied by infrared spectroscopy. was formed by reacting powder with gas dissolved in liquid . The ion was identified by a broad absorption at , a shoulder at and evidence of the sharp absorption just below in the infrared spectrum. The low-frequency modes of at 527 and were unshifted in the reacted powder. The (3) mode of , at , was accompanied by neighbouring absorptions at 1194 and , which were assigned to splitting of the triply degenerate mode. Three strong broad peaks at 1549, 1406 and observed in the spectra were assigned to splitting of the threefold degenerate mode of pristine at . Heat treatments of the sample, with temperatures ranging up to , were performed to thermally decalate the sample and to aid in identifying the infrared modes. The ion, in the sample of reacted with in , was observed in the IR spectra by the broad absorption at and the sharp absorption at . No strong absorption of at was observed, indicating that the sample was not a simple mixture of the two powders. The absorption lines, at 527, 576, 1183 and , were unshifted. However, the mode at showed asymmetric broadening on the low-frequency side and small absorptions flanking the mode. These features, although much less pronounced, may correspond to the shifting and splitting observed in the mode of the compound. The octahedral ion was identified in the sample of powder reacted with by the strong absorption at . The lines were unshifted, but small absorptions flanking the mode were again similar to the absorptions assigned to splitting in the compound.