A number of high-valent nitrido and imido species of ruthenium, osmium, and chromium have been studied by electrospray tandem mass spectrometry. In each case, the mass spectrum shows the molecular ion as the base peak with a minimal degree of fragmentation. The collision-induced dissociation of these complexes may be interpreted in terms of the intrinsic metal-ligand bonds strengths, e.g. M=N > M=O; M=N > M=NR.