The reaction of iodosilane with disodium tetracarbonylferrate (-11) produces tetracarbonyldisilyliron (SiH,),Fe(CO),, 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 1 1 OD, the disilyl compound 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(C0)4,2NMe, is almost involatile a t room temperature ; chemical and i.r. spectral evidence suggest that it is (SiH,,NMe,),Fe(CO),.A silicon-iron compound, (C,H,)Fe(CO),SiMe,, was the first molecular silicon-transition-metal compound to be prepared 2 [equation (l)]. Despite the great current interest in Main Group IV-transition-metal bonded c~mpounds,~ over ten years passed before other Si-Fe compounds were prepared. The reaction of trichlorosilane with Fe(CO), and [(C,H,)Fe(CO),], produced [SiCl,Fe(CO),!, and (C,H,)Fe(CO)2SiC1,,3, while the preparation and 1.r. spectra of cis-aiid trans-(SiCl,),Fe(CO), and cis-(SiEt,),Fe(CO), have also been described 4 9 5 [equations (1) and (2)]. /C,H,)Fe(CO),Na + fble,SiCl+ (C,H,)Fe(CO),SiMe, + NaCf (1) (2) heat 6SiR,H -i-Fe,(CO)l, -+-3(SiR,),Fe(CO), -+ 3H, (R = C1, refs. 4 and 5; R = Et; ref. 4; cf. ref. 6)Recently the preparation of some chlorophenylsilyliron compounds and the displacement of carbonyl 1