Activated Complex
The transient arrangement of atoms present at the transition state, poised between reactants and products.
Unit
kJ/mol
In depth
The activated complex is not an intermediate: it sits at a maximum on the energy profile and decomposes immediately in one direction or the other. Its concentration is treated as being in quasi-equilibrium with the reactants, which is the central assumption of transition state theory.
Examples in the real world
The [HO···CH₃···Br]⁻ species in the hydrolysis of bromomethane.