The title compound, 1,1'-ferrocenediylbis(diphenylphosphine oxide) dih
ydrate, [Fe(C17H14OP)2].2H2O, was obtained by oxidation of bis(dipheny
lphosphino)ferrocene with trimethylamine oxide. The Fe atom sits on a
molecular centre of symmetry and the two Cp rings are planar with a st
aggered configuration. The two phosphoryl groups are trans with respec
t to the Fe(Cp)2 group.