Multiplicative prefixes are used in chemical names to indicate the number of identical chemical entities. While the multiplicative prefixes di, tri, tetra, penta, etc., are used in the case of simple entities such as monoatomic ligands, in the case of composite ligand names or in order to avoid ambiguity, the multiplicative prefixes bis, tris, tetrakis, pentakis, etc., are used. For the latter, the modified entity is placed within parentheses. For example, [Fe(CCPh)2(CO)4] is named tetracarbonylbis(phenylethynyl)iron. Citing units first, then tens, hundreds and so on is used to build up composite multiplicative prefixes like pentatriaconta (or pentatriacontakis) for 35.
Interested readers are recommended to see the following source to find more about multiplicative prefixes and in general about general nomenclature rules:
N.G. Connelly, T. Damhus, R.M. Hartshorn, and A.T. Hutton, “Nomenclature of Inorganic Chemistry”, IUPAC Red Book, IUPAC & RSC Publishing, Cambridge (2005)