Heteroleptic triphenylphosphine carbonyl palladium clusters of different nuclearities were prepared under mild conditions by only varying the amount of ligand (PPh 3 ) used in the synthesis: three different clusters were successfully isolated after CO bubbling in a solution of [Pd 2 (dba) 3 ] (dba=dibenzylideneacetone) with 3, 1 or 0.5equiv of PPh 3 , which led, respectively, to [Pd 4 (CO) 5 (PPh 3 ) 4 ] (1), [Pd 10 (CO) 12 (PPh 3 ) 6 ] (2) and [Pd n (CO) x (PPh 3 ) y ] (3) (n≈24). The molecular structures of compounds 1 and 2 were determined by X-ray crystallography. The metal cores in these compounds were shown to consist in a butterfly for 1 and a bridged octahedron for 2. Compound 3 was shown to be at the boundary between molecular clusters and colloidal particles with tentative formulation arising from characterization data. These three clusters and the known [Pd 10 (CO) 12 (PBu 3 ) 6 ] and [Pd 12 (CO) 15 (PBu 3 ) 7 ] were submitted to NaBH 4 reduction. The Pd 4 cluster 1 did not react. The colloidal Pd n species led to no isolable product. By contrast, the two Pd 10 and the Pd 12 clusters led to reduction products, isolated as NEt4+ salts. In the case of the reduced Pd 12 cluster, its structure was resolved by X-ray crystallography: the metal core consists of a face-capped octahedron. The reduced species reacted readily with Au(PPh 3 ) + , confirming their anionic nature.