Hydrogen adsoprtion on Li-decorated MOF-5. (A–C) Optimized geometries of adsorbed hydrogen molecules on BDC:2Li in the framework of MOF-5 with one H2 per Li (A), two H2 per Li (B), and three H2 per Li (C). C, black; Li, green; H, gray. The rest of the framework has been omitted for clarity. (D) Schematic drawing of the C atoms in the BDC unit.