Transition state

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 S_N2 reaction of bromoethane with a hydroxide anion:

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]

^ Solomons, T.W. Graham & Fryhle, Craig B. (2004). Organic Chemistry (8th ed.). John Wiley & Sons, Inc. ISBN 0-471-41799-8.
^ The calculation used a B3LYP functional and a 6-31+G* basis set.
^ ^a ^b Peter Atkins and Julio de Paula, Physical Chemistry (8th ed., W.H. Freeman 2006), p.809 ISBN 0-7167-8759-8

[1] Solomons, T.W. Graham & Fryhle, Craig B. (2004). Organic Chemistry (8th ed.). John Wiley & Sons, Inc. ISBN 0-471-41799-8.

[2] The calculation used a B3LYP functional and a 6-31+G* basis set.

[Atkins-3] Peter Atkins and Julio de Paula, Physical Chemistry (8th ed., W.H. Freeman 2006), p.809 ISBN 0-7167-8759-8

[1]

[2]

[3]