Selectivity factor

{
  "id": "MLC-T-CHM-010689",
  "term": "Selectivity factor",
  "field": "Chemistry",
  "definition": "A measure of how strongly a monosubstituted benzene discriminates between the para and meta positions in a substitution, usually electrophilic, defined as the base-10 logarithm of the para partial rate factor divided by the meta partial rate factor. A partial rate factor is the rate at one position of the substituted ring relative to a single position of benzene. The selectivity factor is much larger for bromination of toluene than for its nitration.",
  "subject": "Organic and Biomolecular Chemistry",
  "see_also": [
    "aromatic",
    "electrophile",
    "partial rate factor",
    "selectivity",
    "substitution reaction"
  ],
  "references": [
    "PAC, 1994, 66, 1077. 'Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)' on page 1162 (https://doi.org/10.1351/pac199466051077)"
  ],
  "url": "https://mlchart.com/terminology/chemistry/selectivity-factor/"
}