Solid component of catalyst for the (co) polymerization of ethylene and -olefins

The present invention relates to a solid component of catalyst, the procedure for its preparation and its use in procedures for the (co)polymerization of ethylene and -olefins. A solid component of catalyst for the (co)polymerization of ethylene and -olefins contains magnesium-carboxylate bonds and transition metal-carboxylate and can be represented by the formula:wherein:M is at least one metal selected from titanium, vanadium, zirconium and hafnium,X is a halogen excluding iodine, andR is an aliphatic, cycloaliphatic or aromatic hydrocarbon radical, containing at least 4 carbon atoms.A description follows of the preparation of a solid component of catalyst (I) and its use in procedures for the (co)polymerization of ethylene and -olefins.