Various sized siloxides (Cy3SiO > (Bu3SiO)-Bu-t > (Bu2PhSiO)-Bu-t > (Bu2MeSiO)-Bu-t similar to (Pr2BuSiO)-Pr-i-Bu-t > (Pr3SiO)-Pr-i > (Bu2HSiO)-Bu-t) were used to make (R2R'SiO)(3)TaCl2 (R = Bu-t, R' = H (1-H), Me (1-Me), Ph (1-Ph), Bu-t (1); R = Pr-i, R' = Bu-t (1-Pr-i(2)); R = R' = Pr-i (1-Pr-i(3)); R = R' = (c)Hex (Cy)). Product analyses of sodium amalgam reductions of several dichlorides suggest that [(R2R'SiO)(3)Ta](2)(mu-Cl)(2) may be a common intermediate. When the siloxide is large (1-Bu-t), formation of the Ta(III) species ((Bu3SiO)-Bu-t)(3)Ta (6) occurs via disproportionation. When the siloxide is small, the Ta(IV) intermediate is stable (e.g., [((Pr3SiO)-Pr-i)(3)Ta](2)(mu-Cl)(2) (2)), and when intermediate sized siloxides are used, solvent bond activation via unstable Ta(III) tris-siloxides is proposed to occur. Under hydrogen, reductions of 1-Me and 1-Ph provide Ta(IV) and Ta(V) hydrides [((Bu2MeSiO)-Bu-t)(3)Ta](2)(mu-H)(2) (4-Me) and ((Bu2PhSiO)-Bu-t)(3)TaH2 (7-Ph), respectively.