Abstract: The invention relates to metallocene compounds having the formula (I): (CpYq)mMRnBo  (I) wherein: Cp or each same or different Cp is a non-substituted or substituted, fused or non-fused, homo(iso)cyclic or heterocyclic cyclopentadienyl ligand, indenyl ligand, tetrahydroindenyl ligand, fluorenyl ligand or octahydrofluorenyl ligand, Y or each same or different Y is a substituent at the cyclopentadienyl ring of said ligand Cp having the following structure (II): wherein: D is an element of Group 14 of the Periodic Table (IUPAC), R1, R2 and R3 are the same or different and are each one of a hydrogen, a halogen, a substituted or unsubstituted C1-C10 hydrocarbyl group, a substituted or unsubstituted C1-C10 hydrocarbyloxy group, a C1-C12 organosilicon group, or at least two of R1, R2 and R3 form together with D a C4-C20 ring structure; M is a transition metal of Group 4 of the Periodic Table (IUPAC) and is bound to the ligand Cp or ligands Cp in an &eegr;5 bonding mode; R or each same o

Abstract: According to the invention a new catalyst precursor is obtained, in which alkoxy or siloxy substitution in the 2-position of 5-membered ring of indenyl compound has been carried out. Thereby a metallocene compound is achieved, in which an oxygen atom is directly bonded to the 2-position of a pentahapto indenyl moiety. The catalyst precursors can be used as components for olefin polymerization catalysts.