The structure and stability of B-5, B-5(+) and B-5(-) clusters have been investigated at the B3LYP/6-311+G* and MP2/6-311+G* levels of theory. Eight B-5, seven B-5(+), and seven B-5(-) isomers are identified. Of these 22 species, 16 have not been reported previously. The planar five-membered ring structures, 1 and 1(+), are found to be the most stable on the neutral and cationic surfaces, respectively, in agreement with the results reported previously. The most stable B-5(-) isomer has an arrangement of atoms similar to the neutral 1. Upon the addition of an electron, the number of bonds increases from five to seven in this anion. Natural bond orbital (NBO) analysis suggests that there are three-centered bonds in both the neutral structure 1 and the anionic structure 1(-), as well as the multicentered a centripetal bond in the cationic structure 1(+). The calculated nucleus-independent chemical shifts (NICS) of the structures 1, 1(+), and 1(-) are all negative values, which indicates their aromatic characters. The higher degree of aromaticity and the multicentered a centripetal bond are responsible for the special stability of the lowest-energy B-5(+) isomer.