I'm very confused about the differences between these methods. From my textbook, it states that the HuckelHückel method only takes into account the piπ bonding interactioninteractions, while the Extended Huckel will takeextended Hückel method takes into account all the valence electrons. But what exactly does this do?
Because toTo my knowledge, the Ss, Pzpz, Pxpx, and Pypy orbitals are all orthogonal to one another and wouldn't mix anyways. IsAre shielding effects the only thing accounted for by the extended Hückel theory shielding effects?