# Question #8fe7a

Dec 14, 2014

Supercritical carbon dioxide is a fluid state of $C {O}_{2}$ at which both the temperature and the pressure exceed the critical point - the highest temperature and pressure at which the substance can exist as a vapor and liquid in equilibrium - of ${31}^{\circ} C$ ( or 304.15K) and $73 a t m$.

If you look at $C {O}_{2}$'s phase diagram, this region corresponds to the upper-right portion of the diagram. When in a supercritical state, $C {O}_{2}$ has both gas-like and liquid-like qualities - it acts as a supercritical fluid for which distinct gas and liquid phases do not exist.

Supercritical fluids can dissolve materials like a liquid and effuse through solids as a gas, and are often used as a substitute for organic solvents for industrial or laboratory processes. This dissolving ability can be apllied to extract, purify, recristallize, infuse, or fractionate various materials

By controlling its temperature and/or pressure, supercritical $C {O}_{2}$ can be made to dissolve a wide range of materials.

Here's a YouTube video on supercritical $C {O}_{\circ}$