Metastability is the ability of a non-
equilibrium state to persist for a long period of time. Usually metastability is due to a relatively slow
phase transformation. For example at room temperature
diamonds are metastable because the phase transformation to the stable
graphite form is extremely slow. At higher temperatures the rate of phase transformation is increased and the diamond will transform to graphite. The bonds between the building blocks of
polymers such as
DNA,
RNA and
proteins are also metastable.
In electronics, the flip flop is a device that suffers from metastability. It has two well-defined stable states, but under certain conditions it can hover between them for longer than the normal decision time.