In this work, the correlation between geometry and energy of structures were studied. Geometrical parameters including bond lengths and XYZ coordinated of optimized structures, C4H4M, C4H6M and C4H8M (M = C, Si, Ge. Sn and Ph) were calculated. The change order of Delta G(1-s) is (except for M = C): C4H6M > C4H8M > C4H4M.