The complex [PBu4](2)[Pd-2(mu-CO)(2)Cl-4] has been prepared in high yields by carbonylation of [PBu4](2)[Pd2Cl6], Methanol, potassium acetate, or CO readily reacted under ambient conditions to quantitatively afford a series of dipalladium(1) complexes, namely [Pd-2(mu-CO)(2)Cl-3(OCH3)](2-), [Pd-2(mu-CO)(2)Cl-3(OC(O)CH3)](2-), [Pd-2(mu-CO)(2)Cl-3(CO)](-), and [Pd-2(mu-CO)(2)Cl-2(OCH3)(CO)](-), all of which have the Pd-2(mu-CO)(2) core preserved. All these complexes have been characterized by infrared and NMR spectroscopies; the high v(CO) stretching wavenumbers observed and the diamagnetic character of these complexes prompted us to perform theoretical calculations to describe the electronic structure of the Pd-2(mu-CO)(2) core and to gain an intimate description of the Pd-CO bonds. The pairing of the two lonely electrons of the Pd d(9) atoms is due to the delocalization along the CO bridging ligands.