Phase rule

{
  "id": "MLC-T-CHM-013385",
  "term": "Phase rule",
  "field": "Chemistry",
  "definition": "A thermodynamic relationship, F = C − P + 2, that relates the number of degrees of freedom (F) in a closed system at equilibrium to the number of components (C) and the number of phases (P). The degrees of freedom represent the number of intensive variables, such as temperature or pressure, that can be independently varied without changing the number of phases. For the water system with one component, the coexistence of solid, liquid, and vapor phases (P=3) occurs only at the triple point, where F=0.",
  "subject": "Inorganic Chemistry",
  "see_also": [
    "degrees of freedom"
  ],
  "references": [
    "PAC, 1994, 66, 577. 'Definitions of terms relating to phase transitions of the solid state (IUPAC Recommendations 1994)' on page 588 (https://doi.org/10.1351/pac199466030577)"
  ],
  "url": "https://mlchart.com/terminology/chemistry/phase-rule/"
}