Abstract Diamagnetic Technetium(V) complexes of general formulae [TcNX 2 (Ph 3 Y) 2 ] and [TcNX 3 (Me 2 PhP) 3 ] (X = Cl, Br; Y = P, As) were prepared starting from TcNCl 4 − and TcNBr 4 − , respectively and were characterized. Ligand exchange rates with diethyldithiocarbamate, et 2 dtc − and N-(N″-morpholinylthiocarbonyl)benzamidinate, morphtcb − , were determined.