The geometric parameters of various configurations of B4 clusters have been optimized using an energy gradient method at the level of ab initio 6-13G. The correlation energy of each electronic state corresponding to a given one in seven geometries is calculated with the CI (CI). By the anal. of normal coordinates, the three of stable and metastable structures are determine, and the energy order of these states is: 1Ag(D2h) <1 A1(C2v) <3 A1(Td) <1 A1(Td). In addition, the bonding behavior in above states has been discussed using the LMO method.

Key words: BORON, CHEMICAL BONDS, ELECTRONIC STATES, AB INITIO CALCULATION, MOLECULAR ORBITAL THEORY