Supersaturated Solution
An unstable solution containing more dissolved solute than the equilibrium solubility at that temperature.
Unit
mol/L
In depth
Supersaturation is achieved by dissolving solute at a high temperature and cooling slowly without disturbance, so no nucleation site is available. The state is metastable: a single seed crystal, a scratch or a shock triggers rapid crystallisation and releases the enthalpy of crystallisation as heat.
Examples in the real world
A hand warmer of supersaturated sodium acetate solidifying instantly when its metal disc is clicked.