Hydrogen-deuterium exchange in hydride chemistry: Dihydrogen bonded complexes as key intermediates

► The hydrogen-deuterium exchange mechanism for hydrides is analyzed. ► The dihydrogen bond determines the selectivity of [1,10-B10H8D2]2− formation. ► The transition state for the H/D exchange resembles the non-classical (η2-H2) complex. ► The possibilities of η2-H2 complex stabilization is found.