The heavier group 15 analogues of benzene, cyclobutadiene and their valence isomers (M 6 and M 4, M = P, As, Sb and Bi)

Abstract

The structures and stability of the benzene, Dewar benzene, benzvalene and prismane structures of M 6 (M = P, As, Sb and Bi) are investigated by means of ab initio molecular orbital calculations. The prismane structure becomes the most stable as M becomes heavier. An interesting finding is that the heavier group 15 atoms are much less reluctant to form planar benzene-like structures than the heavier group 14 atoms. The structures and stability of the cyclobutadiene and tetrahedrane structures of M 4 are also investigated.