B3LYP/6-31G* density functional theory calculations have been carried out on the structure and stability of seven B24N24 clusters. It is found that the new proposed isomer with two octagons, sixteen hexagons and eight squares in S-8 symmetry is more stable than the isomer with six octagons, eight hexagons and twelve squares in 0 symmetry by 60.4 kcal/mol, and the isomer with twenty hexagons and six squares in S-4 symmetry by 2.8 kcal/mol. The fullerene-like isomer is much higher in energy (148.6 kcal/mol). (C) 2004 Elsevier B.V. All rights reserved.