Ab initio (MP2) and density functional theory (DFT) calculations for six neutral (structures 1-6), six cationic (structures 1(+)-6(+)) and six anionic (structures 1(-)-6(-)) isomers of B-7 Clusters have been performed. With only a few exceptions, all isomers are genuine minima. The hexagon capped by an atom structures (C-2v symmetry) are global minima for B-7 (1) and B-7(-) (1(-)) and the hexagonal pyramid structure (C-6v symmetry) is the most stable B-7(-) (1(-)). The aromatic natures of I and 1(+), as well as the anti-aromatic character of 1(-) are also discussed. (C) 2004 Elsevier B.V. All rights reserved.