A composition comprising a mixture of racemic and meso isomers of metallocene compounds having the formula: R 9 L 1 L 2 M 1 R 1 R 2 (formula 1 a) where L 1 and L 2 are identical or different ligands and are each a substituted mononuclear or polynuclear hydrocarbon radical selected from the group consisting of substituted indenyl, azulenyl, fluorenyl, azapentalenyl, thiapentalenyl and oxapentalenyl, which form a sandwich structure with atom M 1 therebetween, R 1 and R 2 are identical or different and are each selected from the group consisting of a hydrogen atom, an alkyl group of from 1 to about 10 carbon atoms, an alkoxy group of from 1 to about 10 carbon atoms, an aryl group of from 6 to about 20 carbon atoms, an aryloxy group of from about 6 to about 10 carbon atoms, an alkenyl group of from 2 to about 10 carbon atoms, an OH group, a halogen atom, or a NR 2 32 group, where R 32 is selected from the group consisting of an alkyl group of from 1 to about 10 carbon atoms and an aryl group of from 6 to about 14 carbon atoms, or R 1 and R 2 form one or more ring system(s), M 1 is a metal of group IVb of the Periodic Table of the Elements, R 9 is a bridge between the ligands L 1 and L 2 having the structure: where if R 40 and R 41 are identical, R 40 and R 41 are selected from the group consisting of propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, cyclo-pentyl, cyclopentadienyl or cyclohexyl, and if R 40 and R 41 are different, R 40 is selected from the group consisting of butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, cyclopentyl, cyclopentadienyl and cyclohexyl, and R 41 is selected from the group consisting of methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, cyclopentyl, cyclopentadienyl and cyclohexyl, M 12 is selected from the group consisting of silicon and germanium, and wherein the mixture of racemic and meso isomers as isolated from the reaction mixture, without any subsequent separation of racemic or pseudoracemic isomers from meso or pseudomeso isomers, has a weight ratio of racemic to meso isomers of greater than 5:1. where L 1 and L 2 are identical or different ligands and are each a substituted mononuclear or polynuclear hydrocarbon radical selected from the group consisting of substituted indenyl, azulenyl, fluorenyl, azapentalenyl, thiapentalenyl and oxapentalenyl, which form a sandwich structure with atom M 1 therebetween, R 1 and R 2 are identical or different and are each selected from the group consisting of a hydrogen atom, an alkyl group of from 1 to about 10 carbon atoms, an alkoxy group of from 1 to about 10 carbon atoms, an aryl group of from 6 to about 20 carbon atoms, an aryloxy group of from about 6 to about 10 carbon atoms, an alkenyl group of from 2 to about 10 carbon atoms, an OH group, a halogen atom, or a NR 2 32 group, where R 32 is selected from the group consisting of an alkyl group of from 1 to about 10 carbon atoms and an aryl group of from 6 to about 14 carbon atoms, or R 1 and R 2 form one or more ring system(s), M 1 is a metal of group IVb of the Periodic Table of the Elements, R 9 is a bridge between the ligands L 1 and L 2 having the structure: where if R 40 and R 41 are identical, R 40 and R 41 are selected from the group consisting of propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, cyclo-pentyl, cyclopentadienyl or cyclohexyl, and if R 40 and R 41 are different, R 40 is selected from the group consisting of butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, cyclopentyl, cyclopentadienyl and cyclohexyl, and R 41 is selected from the group consisting of methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, cyclopentyl, cyclopentadienyl and cyclohexyl, M 12 is selected from the group consisting of silicon and germanium, and wherein the mixture of racemic and meso isomers as isolated from the reaction mixture, without any subsequent separation of racemic or pseudoracemic isomers from meso or pseudomeso isomers, has a weight ratio of racemic to meso isomers of greater than 5:1.