Abstract: The electronic structure and coordinating activation of chemical bonds of η~6-benzene complex of neodymium have been studied by INDO method. The results show that the coordination of NdCl_3 to AlCl_3 through six μ_2-Cl may decrease the Lewis acidity of the Nd ion, the charge difference on Nd and Cl, and polarity of Nd—Cl bonds, which leads to the increasing of the solubility of NdCl_3 in benzene and the stability of the η~6-benzene complex of neodymium.
The coordination of benzene molecule to neodymium ion decreases the strength of C—C and C—H bonds in benzene and enhances the alkylation affinity of the benzene ring obviously.

Key words: Rare earth, Neutral benzene complex, Bond, Coordinating activation