dotted green line shows the anomalous behavior of water
Points
Triple Point
the temperature and pressure at which the solid, liquid, and vapor phases of a pure substance can coexist in equilibrium.
Critical Point
the endpoint of a phase equilibrium curve. The most prominent example is the liquid-vapor critical point, the end point of the pressure-temperature curve that designates conditions under which a liquid and its vapor can coexist. At higher temperatures, the gas cannot be liquefied by pressure alone. At the critical point, defined by a critical temperatureTc and a critical pressurepc, phase boundaries vanish