Abstract: In the course of prolonged interaction in the system consisting of [99Tc(hfa)(CO)4] (hfa is the anion of 1,1,1,5,5,5-hexafluoroacetylacetone), triphenylphosphine (PPh3) or pyridine (py), and CCl4, the hfa anion is gradually displaced by the chloride ion with the formation of the complexes fac- and mer-[99TcCl(CO)3(PPh3)2] and fac-[99TcCl(CO)3(py)2]. The crystal and molecular structures of the complexes were determined. The complex fac-[99TcCl(CO)3(PPh3)2] is the first structurally confirmed example of technetium(I) tricarbonyl bis(triphenylphosphine) complexes of facial structure.