The reaction of iodosilane with disodium tetracarbonylferrate (–II)produces tetracarbonyldisilyliron (SiH3)2Fe(CO)4, together with some hydridotetracarbonylsilyliron and dihydridotetracarbonyliron. Physical properties of the two silyl–iron derivatives reported include their i.r. spectra, from which a cis-octahedral structure is inferred. At 110°, the disilyl compounds begins to decompose in vacuo, yielding hydrogen, silane, hydridotetracarbonylsilyliron, and a brown solid. Water and hydrogen chloride break the Si–Fe bond, giving disiloxane, or chlorosilane and hydridoiron derivatives. The adduct (SiH3)2Fe(CO)4,2NMe3 is almost involatile at room temperature; chemical and i.r. spectral evidence suggest that it is (SiH3,NMe3)2Fe(CO)4.