Fe-57 Mossbauer spectra of bis(isocyclopentadienyl)iron and its cationic fo
rm have been determined over the temperature range 90 less than or equal to
T less than or equal to 300 K, and the hyperfine interaction and lattice d
ynamical parameters extracted from these data are compared to a number of s
tructurally related oganometallics. The metal d-orbital involvement in the
bonding to the cyclic ligands is discussed in detail.