Hammett equation

{
  "id": "MLC-T-CHM-005087",
  "term": "Hammett equation",
  "field": "Chemistry",
  "definition": "A linear free-energy relationship that correlates the reaction rates or equilibrium constants for a series of substituted aromatic compounds with electronic substituent constants. The equation, log(k/k0) = ρσ, quantifies the effect of substituents on reactivity. Here, k and k0 are rate or equilibrium constants for the substituted and unsubstituted compounds, respectively, σ is the substituent constant, and ρ is the reaction constant.",
  "synonyms": [
    "Hammett relation",
    "ρσ-equation"
  ],
  "subject": "Organic and Biomolecular Chemistry",
  "see_also": [
    "ρ-value",
    "Taft equation",
    "Yukawa-Tsuno equation",
    "equilibrium constant",
    "functional group",
    "σ-constant"
  ],
  "references": [
    "PAC, 1994, 66, 1077. 'Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)' on page 1119 (https://doi.org/10.1351/pac199466051077)"
  ],
  "url": "https://mlchart.com/terminology/chemistry/hammett-equation/"
}