Written by Grant England AP225, Fall 2011
A metastable state is a state of a system which is stable over one time-scale and unstable over another timescale. It represents a local, but not global, minimum in the energy landscape of the system. In chemistry, a reaction may not take place quickly if the reactants are stuck in a metastable state intermediate between the initial reactants and desired products. In order to progress to the final desired products, the reactants must overcome the activation energy of the reaction to transfer from the metastable state to the stable state. In chemistry, catalysts can be used to lower this activation energy; in biology, enzymes act as the catalysts.