The novel bis(ferrio)silanols [Cp(OC)2Fe]2Si(X)OH [X = H (2), OH (4), Cl (7)] are obtained via hydrolysis of [Cp(OC)2Fe]2Si(H)Cl (1) or via oxygenation of the bis(ferrio)hydridosilanes [Cp(OC)2Fe]2Si(H)X [X = Cl (1), H (6)] with dimethyldioxirane. Subsequent condensation reactions with chlorodimethylsilane yield the bis(ferrio)siloxanes [Cp(OC)2Fe]2Si(X)(OSiMe2H) [X = H (12), OSiMe2H (13), OH (15)]. In an analogous manner the hetero-bismetalated silanol [Cp(OC)2Fe][Cp(OC)2(Me3P)W]Si(Me)OH (11) and the disiloxane [Cp(OC)2Fe][Cp(OC)2(Me3P)W]Si(Me)(OSiMe2H) (14) have been prepared. The influence of the transition metal substituents on the chemical and spectroscopic properties of these compounds has been investigated. The X-ray structure analyses of the bis(ferrio)silanol [Cp(OC)2Fe]2Si(H)OH and the bis(ferrio)dimethoxysilane [Cp(OC)2Fe]2Si(OCH3)2 (5)generated via methanolysis of [Cp(OC)2Fe]2SiCl2 (3)are presented.