Abstract: The present invention discloses a metallocene catalyst component based on a Group IIIb metal of the periodic Table and a bridged heteroatom-fluorenyl ligand. It also discloses its method of preparation and its use in polymerisation.

Abstract: Supported stereospecific catalysts and processes for the stereotactic propagation of a polymer chain derived from ethylenically unsaturated monomers which contain three or more carbon atoms or which are substituted vinyl compounds, specifically alpha olefins, particularly the polymerization of propylene to produce syndiotactic or isotactic polypropylene. The supported metallocene catalyst comprises a stereospecific metallocene catalyst and a co-catalyst component comprising at least one of an alkyl alumoxane and an alkylaluminum compound. Both the metallocene catalyst and the co-catalyst are supported on a particulate silica support comprising silica particles having an average particle size of 5-40 microns and an average effective pore size of 50-200 angstroms. The silica support further has a differential pore size distribution of a pore volume of at least 0.01 cm3/g. within a range having a maximum pore width of no more than 300 angstroms.