Metallocene compound

A metallocene of the formula I ##STR9## where M.sup.2 is a metal of group IVb, Vb or VIb of the Periodic Table,

• the radicals R.sup.1 are identical or different and are a hydrogen atom, 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,
• the radicals R.sup.2 are identical or different and are hydrogen, 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, a C.sub.1 -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, a -NR.sup.10, --OR.sup.10, --SR.sup.10, --OSiR.sub.3.sup.10, --SiR.sub.3.sup.10 or --PR.sub.2.sup.10 radical, where 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,
• the radicals R.sup.3 are identical or different and are a hydrogen atom, a halogen atom, a C.sub.1 -C.sub.20 -alkyl group, a C.sub.1 -C.sub.20 -fluoroalkyl group, a C.sub.6 -C.sub.30 -aryl group, a C.sub.6 -C.sub.30 -fluoroaryl group, a C.sub.1 -C.sub.20 -alkoxy group, a C.sub.2 -C.sub.20 -alkenyl group, a C.sub.7 C.sub.40 -arylalkyl group, a C.sub.8 -C.sub.40 -arylalkenyl group, a C.sub.7 -C.sub.40 -alkylaryl group, a --NR.sub.2.sup.10, --OR.sup.10, --SR.sup.10, --OSiR.sub.3.sup.10, --SiR.sub.3.sup.10 or --PR.sub.2.sup.10 radical, where 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, or two or more radicals R.sup.3 together with the atoms connecting them form a ring system, but radicals R.sup.3 are not hydrogen when all radicals R.sup.4 are hydrogen,
• the radicals R.sup.4 are identical or different and are a hydrogen atom, a halogen atom, a C.sub.1 -C.sub.20 -alkyl group, a C.sub.1 C.sub.20 -fluoroalkyl group, a C.sub.6 C.sub.30 -aryl group, a C.sub.6 -C.sub.30 -fluoroaryl group, a C.sub.1 -C.sub.20 -alkoxy group, a C.sub.2 -C.sub.20 -alkenyl group, a C.sub.7 -C.sub.40 -arylalkyl group, a C.sub.8 C.sub.40 -arylalkenyl group, a C.sub.7 -C.sub.40 -alkylaryl group, a --NR.sub.2.sup.10, --OR.sup.10, --SR.sup.10, --OSiR.sub.3.sup.10, --SiR.sub.3.sup.10 or --PR.sub.2.sup.10 radical where 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, or two or more radicals R.sup.4 together with the atoms connecting them form a ring system, but all radicals R.sup.4 are not hydrogen when all radicals R.sup.3 are hydrogen, R.sup.5 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, 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, a --NR.sub.2.sup.10, --OR.sup.10, --SR.sup.10, --OSiR.sub.3.sup.10, --SIR.sub.3.sup.10 or --PR.sub.2.sup.10 radical, where 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.6 is a hydrogen atom, 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, 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 -alkyloxy group, a C.sub.8 -C.sub.40 -arylakenyl group, a --NR.sub.2.sup.10, --OR.sup.10, --SR.sup.10, --OSiR.sub.3.sup.10, --SIR.sub.3.sup.10 or --PR.sub.2.sup.10 radical, where 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.7 is ##STR10## .dbd.BR.sup.11, .dbd.AlR.sup.11, --Ge--, --Sn--, --0--, --S--, .dbd.SO, .dbd.SO.sub.2,.dbd.NR.sup.11, .dbd.CO, =PR.sup.11 or .dbd.P(O) R.sup.1l,
• where
• 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.20 -alkyl group, a C.sub.1 -C.sub.20 -fluoroalkyl group, a C.sub.6 -C.sub.30 -aryl group, a C.sub.6 -C.sub.30 -fluoroaryl group, a C.sub.1 -C.sub.20 -alkoxy group, a C.sub.2 -C.sub.20 -alkenyl group, a C.sub.7 -C.sub.40 -arylalkyl group, a C.sub.5 -C.sub.40 -arylalkenyl group, 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 together with the atoms connecting them form a ring, M.sup.1 is silicon, germanium or tin,
• R.sup.8 and R.sup.9 are identical or different and are a hydrogen atom, a halogen atom, a C.sub.1 -C.sub.20 -alkyl group, a C.sub.1 -C.sub.20 -fluoroalkyl group, a C.sub.6 -C.sub.30 -aryl group, a C.sub.6 -C.sub.30 -fluoroaryl group, a C.sub.1 -C.sub.20 -alkoxy group, a C.sub.2 -C.sub.20 -alkenyl group, a C.sub.7 -C.sub.40 -arylalkyl group, a C.sub.8 -C.sub.40 -arylalkenyl group, a C.sub.7 -C.sub.40 -alkylaryl group, or R.sup.8 and R.sup.9 together with the atoms connecting them form a ring,
• m and n are identical or different and are zero, 1 or 2, where m plus n is zero, 1 or 2, wherein the two indenyl ligands have substitution patterns different from one another on the six-membered ring.