Supercritical Fluid
A substance held above both its critical temperature and critical pressure, where liquid and gas phases are indistinguishable.
Formula / equation
T > T_c and p > p_c
Unit
K, Pa
In depth
A supercritical fluid combines gas-like diffusivity and low viscosity with liquid-like density and solvent power, and its solvating strength can be tuned continuously by adjusting pressure. This makes it an attractive replacement for hazardous organic solvents.
Examples in the real world
Supercritical CO₂ decaffeinating coffee beans and extracting hop oils; supercritical water oxidising toxic waste.