The geometries, the harmonic vibrational frequencies and the bonding proper
ties have been predicted for cyclic AlS2 and GaS2 species at the density fu
nctional theory (DFT), MPn (n = 2, 3, 4), QCISD(T) and CCSD(T) Levels with
6-311+G (2df) basis set. The novel bonding character was discussed.