In HS, the interaction of H2 is dominated by weak van der Waals forces and results in binding energies of 0.087-0.132 eV. The binding configurations results in significantly longer bond distances with the molecule in a semi-horizontal configuration. The large change in binding energy upon spin crossover provides a promising mechanism for an efficient hydrogen capture/storage because the use of cryogenic conditions can be bypassed, and storage could be performed at RT, provided that the transition to HS occurs at higher temperatures. Thus, the cases of bpac for both Fe and Mn represent promising candidates for this mechanism since the predicted ∆EH-L may be consistent with transition occurring above RT.