Linear free-energy relation

{
  "id": "MLC-T-CHM-006623",
  "term": "Linear free-energy relation",
  "field": "Chemistry",
  "definition": "An empirical correlation in which the logarithm of a rate or equilibrium constant for one reaction series is a straight-line function of the logarithm of the corresponding constants for a second, related series. It reflects a proportionality between the free energy changes in the two sets of reactions. The Hammett equation, log(k/k0) = ρσ, is the best-known example, with σ a substituent constant taken from the ionization of benzoic acids and ρ the sensitivity of the reaction.",
  "synonyms": [
    "linear Gibbs energy relation"
  ],
  "subject": "Organic and Biomolecular Chemistry",
  "see_also": [
    "Brønsted relation",
    "Hammett equation",
    "activation",
    "equilibrium constant",
    "order of reaction",
    "σ-constant"
  ],
  "references": [
    "PAC, 1994, 66, 1077. 'Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)' on page 1136 (https://doi.org/10.1351/pac199466051077)"
  ],
  "url": "https://mlchart.com/terminology/chemistry/linear-free-energy-relation/"
}