Equation describing the equilibrium two-phase state of substances

The equilibrium state of substances in crystal–gas and liquid–gas systems under studied and unstudied conditions is described on the example of silver, nitrogen, and carbon dioxide with a two-parameter equation. The heat of the phase transition of substances from the condensed state to the gaseous state is shown to depend on temperature with one coefficient. The accuracy of calculation of the equilibrium pressure and heat for the transition of substances from the condensed state to the gaseous state is estimated.