Reaction coordinate

In chemistry, reaction coordinate is a name that refers typically to the plotting of one variable of a chemical reaction on the y-coordinate, typically energy or free energy, versus the another variable, such as extent of reaction, species concentration, reaction velocity, etc., on the x-coordinate. Reaction coordinates originated from transition state theory, wherein surface energy plots were developed as a conceptual tool.





















Examples
The following are some examples:

Reaction coordinate depicting the initial state of the reactants on going to the final state of the products through two different pathways, indicating that state variables are path-independent.	A typical drug-receptor reaction coordinate as are used on drug-receptor thermodynamics, showing the activated complex.	An SN-2 reaction coordinate, showing the intermediate transition state.
A generic reaction coordinate, showing that reaction can be spontaneous in both directions (meaning it can just as easily unravel as did it form), and the red area indicating a region of negative free energy change.

External links
● Reaction coordinate – Wikipedia.
● Reaction coordinate – IUPAC Gold Book.

More pages

• Extent of reaction