AM 1 (UHF) type semiempirical quantum chemical calculations have been applied to (Li + nH(2))@C-58 type composite systems. However, 2 less than or equal to n less than or equal to 3 systems could be studied due to the electrostatic behaviour of the C-58 structure. Li atom (n = 0 case) and Li and H-2 (N = 1 case) passed through the electrostatic gate of the composite system and went out of the cage structure during the geometry optimization. Similarly, the systems for n greater than or equal to 4 could not be obtained. Other structures (n = 2, 3 cases) could be investigated. They were found to be stable but endothermic in nature. Some structural and physicochemical data are also given for the present systems. (C) 2004 Elsevier B.V. All rights reserved.