Organometallic complexes based on H-bridged Si3H3⁺ and Ge3H3⁺ ligands were studied at the B3LYP and B3P86 levels. Relativistic effective core potentials (SBKJC-21G and Stuttgart-RSC) and their associated basis sets were used on metals and the 6-31G(d) basis set was used on ligands. All the complexes (A3H3)Co(CO)3 (9, C3v), (A3H3)Rh(CO)3 (10, C3v) and (A3H3)Ir(CO)3 (11, C3v) (A = Si and Ge) are minima and more stable than the complexes based on Si3H3⁺ and Ge3H3⁺ ligands with terminal hydrogens (9aâ 11a). The stability of the bridged systems increases from Si to Ge. Isolobal and isosynaptic analogies connect these complexes with other organometallic complexes (e.g. (μ-H)3Fe3(CO)9(μ3-CMe)) and main group pyramidal systems (e.g. (μ-H)3B3H3(μ3-CH)).