What defines a supercritical fluid?

A supercritical fluid is defined by its ability to exist above both its critical temperature and critical pressure. This state combines properties of both liquids and gases, leading to unique behavior. Specifically, a supercritical fluid can diffuse through solids like a gas, while also dissolving materials like a liquid.

In this context, identifying that a supercritical fluid is a dense fluid phase above critical temperature is crucial. At this state, the fluid does not have distinct liquid and gas phases; instead, it exhibits a single phase with properties that enable it to be utilized in various applications such as extraction processes and chemical reactions.

Understanding the nature and defining characteristics of supercritical fluids is essential for their applications in scientific and industrial contexts, setting them apart from gases, liquids, and solids defined at various temperatures and pressures.