Electronic structure and bonding of the hydrides Mg3TH7 (TÂ =Â Mn, Re) from first principles

► Mg3TH7 have desorption energies within range of MgH2 and covalent intermetallic hydrides. ► From Bader charges, T = Re compound has a lower desorption energy than T = Mn. ► The electronic DOS show insulating compounds with larger band gap for the T = Re. ► Chemical bonding analyses: stronger Mn-H bonding versus Re-H with TH6 octahedra.