Ρ-value

{
  "id": "MLC-T-CHM-010461",
  "term": "Ρ-value",
  "field": "Chemistry",
  "definition": "A quantitative measure in physical organic chemistry that describes the sensitivity of a reaction series to changes in substituent electronic effects. It is a parameter in the Hammett equation, reflecting the susceptibility of the reaction center to electron-donating or electron-withdrawing groups. A positive ρ-value indicates that the reaction is accelerated by electron-withdrawing groups, while a negative value indicates acceleration by electron-donating groups.",
  "synonyms": [
    "rho-value"
  ],
  "subject": "Organic and Biomolecular Chemistry",
  "see_also": [
    "σ-constant",
    "Hammett equation",
    "Taft equation",
    "acidity",
    "electron density",
    "equilibrium constant",
    "order of reaction",
    "substituent atom",
    "substrate",
    "transition state"
  ],
  "references": [
    "PAC, 1994, 66, 1077. 'Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)' on page 1161 (https://doi.org/10.1351/pac199466051077)"
  ],
  "url": "https://mlchart.com/terminology/chemistry/r-value/"
}