Process for the preparation of an olefin polymer

A metallocene compound of the formula I ##STR12## in which M.sup.1 is a metal of group IVb, Vb or VIb of the Periodic Table,

• R.sup.1 and R.sup.2 are identical or different and are hydrogen, a C.sub.1 -C.sub.10 -alkyl group, a C.sub.1 -C.sub.10 -alkoxy group, a C.sub.6 -C.sub.10 -aryl group, a C.sub.6 -C.sub.10 -aryloxy group, a C.sub.2 -C.sub.10 -alkenyl group, a C.sub.7 -C.sub.40 -arylalkyl group, a C.sub.7 -C.sub.40 -alkylaryl group, a C.sub.8 -C.sub.40 -arylalkenyl group or a halogen atom,
• R.sup.3 and R.sup.4 are identical or different and are a halogen atom, a C.sub.1 -C.sub.10 -alkyl group, which can be halogenated, a C.sub.6 -C.sub.10 -aryl group or an --NR.sub.2.sup.10, --SR.sup.10, --OSiR.sub.3.sup.10, --SiR.sub.3.sup.10 or --PR.sub.2.sup.10 radical, in which R.sup.10 is a halogen atom, a C.sub.1 -C.sub.10 -alkyl group or a C.sub.6 -C.sub.10 -aryl group,
• R.sup.5 and R.sup.6 are identical or different and have the meaning mentioned for R.sup.3 and R.sup.4, are additionally can also be hydrogen, ##STR13## in which R.sup.11, R.sup.12 and R.sup.13 are identical or different and are a hydrogen atom, a halogen atom, a C.sub.1 -C.sub.10 -alkyl group, a C.sub.1 -C.sub.10 -fluoroalkyl group, a C.sub.6 -C.sub.10 -aryl group, a C.sub.6 -C.sub.10 -fluoroaryl group, a C.sub.1 -C.sub.10 -alkoxy group, a C.sub.2 -C.sub.10 -alkenyl group, a C.sub.7 -C.sub.40 -arylalkyl group, a C.sub.8 -C.sub.40 -arylalkenyl group or a C.sub.7 -C.sub.40 -alkylaryl group, or R.sup.11 and R.sup.12 or R.sup.11 and R.sup.13 in each case form a ring with the atoms joining them, or R.sup.11 or R.sup.12 with R.sup.8 or R.sup.9 in each case form a ring together with atoms joining them,
• M.sup.2 is silicon, germanium or tin,
• R.sup.8 and R.sup.9 are identical or different and have the meaning mentioned for R.sup.11 and
• m and n are identical or different and are zero, 1 or 2, m plus n being zero 1 or 2.