New bimetallic trihydrides Cp2TaH2(mu-H)M(CO)(5) (M = Cr (2), Mo (3), W (4)) have been prepared by the room-temperature high-yield reaction between Cp2TaH3 (1) and M(CO)(5). The complexes have been characterized by elemental analyses and variable-temperature H-1 NMR and IR spectra. The structures and arrangements of the hydride ligands in complexes 2-4, here the central hydride ligand is bound to M, have been determined from H-1 MMR and H-1 T-1 relaxation time data. It has been shown that structural interpretations of H-1 T-1 measurements, carried out for 1 and bimetallic systems below 295 K, can be made on the basis of the isotropic motion approach and of a model of uncoupled nuclei. The high-temperature saturation transfer experiments in the H-1 NMR spectra have shown complexes 2-4 to be stereochemically nonrigid demonstrating an H-X/H-A exchange on the T-1 NMR time scale. It has been established that the energy barrier of the hydride/hydride exchange is decreased in going from complex 1 to bimetallic systems 2-4.