In this paper, a kind of method to design aluminium nitride cage clusters is presented and the geometrical structures of (AlN)_n (n = 2 ～ 41) clusters are obtained. Using quantum chemistry methods AM1, HF/STO-3G, HF/LANL2DZ and DFT/B3LYP/6-31G to optimize these structures, the geometries with lowest energy for each n were obtained. Moreover, through calculating the bonding energy and energy second difference of the structures with lowest energy, a rule for the stable (AlN)_n clusters was found, which will provide theoretical basis for synthesizing (AlN)_n clusters of large size experimentally.

Key words: ALUMINUM NITRIDE, CLUSTER COMPOUND, CONFIGURATION, STABILITY