As we know, topological studies of some typical reactions
have been carried out by many authors [13–23]. The emphasis
of these studies was on the topological properties of the bonds
of reactants, transition states and products. Recently, a method
has been proposed to determine when the bond is broken or
formed by Zheng [23]. But no one mentioned the relative
variation trend between the breaking bond and the forming
bond along the reaction path. In this article, we proposed a
novel method to determine the relative variation trend between
the breaking bond and the forming bond along the reaction path