Core-shell structures of hydrogen-beryllium clusters are predicted to be higher energy isomers relative to the separate H2 and Ben components, the hydrogen molecule dissociating inside the beryllium cage due to strong charge transfer. Variations of the system shape and stability with the relative orientation of the molecular core inside the metal shell and with its size are analyzed. Pathways and energy barriers for extraction of H2 and for its dissociative attachment to Ben from outside are evaluated. The effect of such endohedral doping on the electronic properties, including dipole moment, electronic excitation, ionization and electron attachment are also examined. © 2012 Wiley Periodicals, Inc.