Conformational and Bonding Analysis of C2H42+

In this report, different models of bonding and structure such as Lewis, VSEPR, Ligand close packing (LCP), VB, qualitative MO and QTAIM have been applied to analyze the Bonds and structures of two equilibrium geometries (planar D2h and perpendicular D2d) of C2H42+. The geometries were optimized at near RHF and MP2 limit using ccpVTZ basis set. While the above bonding models are successfully applied for predicting the low energy isomers of molecules, prior to solving the Schr?dinger equation, it is shown that the cited models fail in predicting the existence of perpendicular, D2d form of C2H42+. In this regard the interpretations of significant energetic stabilization of D2d form over planar isomer has also been revisited. This is attributed to the hidden effect of the Pauli Exclusion principle.