Structures of protonated alane-Lewis base donor-acceptor complexes H4AlXH3+ (X = N, P, and As) and H4AlYH2+ (Y = O, S, and Se) as well as their neutral parents were calculated using ab initio method at the G2 level. All the monocations H4AlXH3(YH2)(+) are Al-H protonated involving hypercoordinated alane with a three-center two-electron (3c-2e) bond and adopt the C-s symmetry arrangement. The G2 energetic results show that the protonated alane-Lewis complexes are more stable than the neutral ones. They also show that this stability decreases when descending in the corresponding periodic table column, from nitrogen (or oxygen) to arsenic (or selenium) atoms: The G2 calculated protonation energies of H3AlXH3(YH2) to form H4AlXH3(YH2)(+) were found to be highly exothermic. The possible dissociation of the cations H4AlXH3(YH2)(+) into H2AlXH3(YH2)(+) and molecular H-2 are calculated to be endothermic.