The singular points and phase diagram of the supercritical region of a substance

This paper suggests using the supercritical point and the maximum fluctuation point on the supercritical isotherm for the analysis of the behavior of various substances in the vicinity of the critical point. These three points lie at the vertices of a triangle that is formed by the supercritical isotherm, the line of the local minima of stability, and the line of maxima of fluctuations. In this triangle, which is called supercritical, the fluctuations and instability behave such that this part of the phase surface is most interesting from the viewpoint of performing various chemical reactions. Here, large fluctuations and the stability of the system rapidly decrease with increasing volume. This region is studied in the approximation of the van der Waals and Van Laar equations.