In general, the same behviour as detailed above may repeat at another temperature T (>T₁). One can on the one hand connect all the saturated vapour phase points at different temperatures and on the other connect all the points representing saturated liquid phase, the locus of such points give rise to the dome-shaped portion X-C-B of the P-V diagram which essentially signifies that at any pressure and volume combination within this dome, the state of the system is biphasic (part gas and part liquid). The region right of the dome B-C represents saturated gas phase while to the left (X-C) the state is saturated liquid. If one continues to conduct the pressurization at increasingly higher temperatures, one eventually arrives at a temperature for which the tie-line is reduced to a point and the P-V curve turns into an inflexion point to the two-phase dome. The temperature which such a behavior obtains is called the critical temperature (T_C), while the pressure at corresponding point of inflexion is termed the critical pressure (P_C).  The molar volume at the point is termed the critical volume, and the state itself the critical point. A fluid which is at a temperature and pressure above the critical point values is said to be in a supercritical state; this is indicated by the hatched region in fig. 2b. As has been shown for the P-V curves for a T > T_C, there exists no liquid phase as the curve passes beyond the two-phase dome region. Thus, the critical temperature is a temperature above which a gas cannot be liquefied by compressing, as can be below it. Compilation ofvalues of critical properties and ω for a large number of substances are available readily from several sources see:srdata.nist.gov). Values of these parameters for some select substances are provided in Appendix II.