Diagram, Chemical

(physicochemical diagram), a graphic representation of the relation between the numerical values of the physical or mechanical properties of a physicochemical system and the values of its parameters (composition, temperature, pressure). Constitution diagrams and composition-property diagrams of binary systems are examples of the simplest chemical diagrams. The number and relative positions of the geometric images of a chemical diagram—points, lines, surfaces, and volumes—make it possible to draw conclusions about the chemical nature, composition, and boundaries of existence of the phases formed by the components of the system without isolating or analyzing these phases.