University Chemistry ›› 2016, Vol. 31 ›› Issue (5): 73-77.doi: 10.3866/PKU.DXHX201601001

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The Forms of Lever Rule in the Phase Diagram of Multi-component Systems

Mei-Ju WEI,Fei-Wu CHEN*(),Xu-Qin LI,Ya-Ping YE,Wen-Xia YUAN   

  • Published:2016-05-23
  • Contact: Fei-Wu CHEN
  • Supported by:


Two forms of the lever rule in the two-phase and three-phase regions of a multi-component system are discussed in this article. As for the two-component system, the cooling curves of solutions are explained with the lever rule in a three-phase line and the freezing point depression equation. A similar form of the lever rule is presented for three points on a line segment in a three-phase diagram region. This equation can be exploited to prepare the solution with desired concentrations of a multi-component system and to draw three-phase diagrams.

Key words: Multi-component system, Lever rule, Phase diagram, Phase equilibrium