Supercooled Liquids
Definition and meaning of Supercooled Liquids in chemistry.
Supercooled liquids are substances that have been cooled below their standard freezing point without transitioning into a solid crystalline state. They remain in a liquid phase because the molecules have not yet formed the highly ordered lattice required for crystallization.
In more detail
Supercooling occurs when a liquid is cooled rapidly or kept extremely pure so that there are no available nucleation sites for crystals to begin forming. The liquid exists in a metastable state; if a seed crystal is introduced or the liquid is disturbed physically, it can freeze rapidly and exothermically. Amorphous solids, such as glass, are technically highly viscous supercooled liquids whose molecules have stopped flowing on any practical human timescale.
Key facts
| Field | Physical Chemistry |
|---|---|
| Formula | H2O |
| State | Metastable liquid below standard freezing point |
| Requirement | Lack of nucleation sites to prevent crystallization |
Pure liquid water (H2O) can be carefully cooled to temperatures as low as -40 degrees Celsius in a very clean container without turning into ice, remaining a supercooled liquid.
Frequently asked questions
How does a supercooled liquid eventually freeze?
It freezes when a nucleation site is provided, such as a dust particle, a seed crystal, or a physical shock, which triggers a rapid phase change.