. . . . "' being the same or different, R is a structural bridge between (CpR4) and (CpR'4) imparting stereorigidity to the metallocene, Me is a Group IIIB, IVB, VB or VIB metal, Q is a hydride, a halogen, an amide or a hydrocarbyl radical, each Q being the same or different, except only one Q can be hydride and p is the valence of Me minus 2; wherein the ionizing ionic compound does not contain an active" . . .