Structural and thermodynamic characteristics of adducts GeX ₄ • nL (n = 1, 2; X = F, Cl, Br; L = NH ₃ , py, bipy, phen) have been calculated by the B3LYP density functional theory method. The enthalpies of sublimation of complexes trans-GeX ₄ • 2py and the adduct GeCl ₄ • bipy have been estimated for the first time. The rearrangement energies of the donor and acceptor fragments and the Ge-N bond energies for the 1:1 and 1:2 complexes have been calculated. While the rearrangement energy for germanium halides is lower by 19-63 kJ mol ^-1 than that for silicon halides, the energy of the donor-acceptor bond in the former case is slightly lower. As a result, germanium adducts are slightly more stable than silicon adducts.