As expected for terminal carbides, our calculations predict short axial M-Ccarbido bonds, which hover around 1.5 Å for Fe and Co, around 1.64 Å for Ru and Rh, and around 1.68 Å for Os and Ir. These distances are only slightly longer (by 0.01-0.02 Å) than the axial M-Nnitrido complexes calculated for the M(L1)(N) series. In an interesting reversal, the M-C single bonds involving the ligands L1 and L2 are slightly longer for Ru and Rh than their 5d congeners Os and Ir, respectively. We have not examined the origin of this reversal, but Pyykkö's covalent radii 24,25,26 echo a similar effect. Thus, while the double-and triple-bond Interestingly, none of the compounds examined exhibits a significant adiabatic EA. In fact, the majority of them exhibit negative EAs and the molecules in M(L2)(C) series exhibit exceptionally large negative EAs for neutral molecules. In other words, these complexes are not expected to give rise to stable gas-phase anions and in solution are expected to exhibit unusually low reduction potentials. The compounds are thus all predicted to be reductively stable.