QUANTUM-CHEMICAL STUDY ON MO2C8 CLUSTER

There is considerable interest in metal-carbon clusters because of the possible applications of metal-carbon cluster to catalytic and new el ectronic materials, pollution control, chemical tracers, superconducti ve materials and in site-specific protein chemistry. In recent years, studies have especially focused on transition-metal carbon clusters. I n this paper, quantum chemical ab initio method is used to study the g eometric and electronic structures of the Mo2C8, cluster. In trying to determine likely candidates for the structure of ground state of Mo2C 8, a number of possible isomeric structures were investigated. The mos t stable structure is found to possess C-2h symmetry, where two Mo ato ms connect directly each other and each Mo atom connects to four carbo n atoms, Mo atom is enclosed by C atoms, so as the spatial effect and bond forming property are concerned, the reactions of Mo2C8- with NH3, H2O are difficult, In fact, experiment had observed Mo2C8- ion are in deed completely unreactive with NH3 and H2O. Furthermore, our calculat ed E(A) of this isomer is 3.6 eV, which is just the upper limit of the experimental value(the experimental value of E(A)(MO(2)C(8)) is betwe en 2.7 +/- 0.2 eV and 3.3 +/- 0.3 eV), and this structure can also exp lain other existing experimental results perfectly.