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Transition state
Configuration of a chemical reaction when potential energy is greatest / From Wikipedia, the free encyclopedia
In chemistry, the transition state of a chemical reaction is a particular configuration along the reaction coordinate. It is defined as the state corresponding to the highest potential energy along this reaction coordinate.[1] It is often marked with the double dagger (‡) symbol.
As an example, the transition state shown below occurs during the SN2 reaction of bromoethane with a hydroxide anion:
![Thumb image](http://upload.wikimedia.org/wikipedia/commons/thumb/4/40/Bromoethane_SN2_reaction.svg/320px-Bromoethane_SN2_reaction.svg.png)
![Thumb image](http://upload.wikimedia.org/wikipedia/commons/thumb/e/e6/Base_hydrolysis_of_bromoethane%2C_TS.png/640px-Base_hydrolysis_of_bromoethane%2C_TS.png)
The activated complex of a reaction can refer to either the transition state or to other states along the reaction coordinate between reactants and products, especially those close to the transition state.[3]
According to the transition state theory, once the reactants have passed through the transition state configuration, they always continue to form products.[3]