A PM3 SCF-MO study of the structure and bonding in the cage systems S4N4 and S4N4X (X = N+, N−, S, N2S, P+, C, Si, B− and Al−)

A PM3 SCF-MO study of the structure and bonding in the cage systems S4N4 and S4N4X (X = N+, N−, S, N2S, P+, C, Si, B− and Al−)