This invention relates to metallocene compositions and their use in the
preparation of catalyst systems for olefin polymerization, particularly
propylene polymerization. The metallocene compositions may be represented
by the formula:
##STR1##
wherein R.sup.9 and R.sup.11 are identical or different and are a Group 14
radical having from 1 to 20 carbon atoms or are each primary, secondary or
tertiary butyl groups, aryl groups, isopropyl groups, fluoroalkyl groups,
trialkyl silyl groups, or other groups of similar size.
