Abstract: On the basis of the analysis of various construction methods of the hybrid orbitals, the conept of the extended basis hybrid orbital has been proposed for the hybrid orbital containing the atomic orbitals of nonvalent shell. Taking the bound conditions into account, we have derived the analytical form of the extended basis hybrid orbital with equivalent characters by using the principle of the maximum overlap. It is found that the hybrid character of one atomic orbital belonging to the central atom depends on its degree of overlap with the ligand orbitals. Some applications of this method have been given.

Key words: Hybeid orbital, Construction method, Extended basis, Maximum overlap