A supercritical fluid is any substance at a temperature and pressure above its critical point. It can seep through solids like a gas, and dissolve materials like a liquid. plus, close to the critical point,
small changes in pressure or temperature result in
large changes in density, allowing many properties of a supercritical fluid to be negligable. Supercritical fluids are used as a substitute for
organic solvents in a range of industrial and laboratory processes.