in benzene stirring of Fe2(CO)9 with silane (24 h), addn. of further Fe2(CO)9 (total molar ratio Fe:Si=2.4:1), stirring (24 h); evapn. (vac., low temp.), dissoln. in hexane, filtration (Florisil), solvent removal, dissoln. in hexane, crystn. of Fe3(CO)12 (-30°C), evapn. of mother liquor; elem. anal.;