Critical point (thermodynamics)

In <a href="/facts/Thermodynamics/q4hIx3yP">thermodynamics</a>, a critical point (or critical state) is the end point of a phase <a href="/facts/Equilibrium_(thermodynamics)/1D7nGm0d">equilibrium</a> curve. One example is the liquid–vapor critical point, the end point of the pressure–temperature curve that designates conditions under which a <a href="/facts/Liquid/t9GkLWzt">liquid</a> and its <a href="/facts/Vapor/PLlojGug">vapor</a> can coexist. At higher temperatures, the gas comes into a <a href="/facts/Supercritical_fluid/rGkUWb7e">supercritical</a> phase, and so cannot be liquefied by pressure alone. At the critical point, defined by a critical temperature Tc and a critical pressure pc, <a href="/facts/Phase_(matter)/NkHXDdN3">phase</a> boundaries vanish. Other examples include the <a href="/facts/Upper_critical_solution_temperature/KAspLK4g">liquid–liquid critical points in mixtures</a>, and the ferromagnet–paramagnet transition (<a href="/facts/Curie_temperature/ygotSuMg">Curie temperature</a>) in the absence of an external magnetic field.

Critical point (thermodynamics) open-in-new

Critical point (thermodynamics)