Leaving group

{
  "id": "MLC-T-CHM-006506",
  "term": "Leaving group",
  "field": "Chemistry",
  "definition": "A fragment, either an atom or a group and either charged or neutral, that separates from the remainder of the substrate during a given reaction. In nucleophilic substitution it departs with the bonding electron pair, as bromide does from benzyl bromide, and is called a nucleofuge, whereas in electrophilic aromatic nitration it is H+, which leaves without the pair. Weakly basic anions such as iodide and tosylate are good nucleofuges because they are stable once detached.",
  "subject": "Organic and Biomolecular Chemistry",
  "see_also": [
    "electrofuge",
    "electrophile",
    "entering group",
    "nucleofuge",
    "solvolysis",
    "substituent atom",
    "substrate"
  ],
  "references": [
    "PAC, 1994, 66, 1077. 'Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)' on page 1134 (https://doi.org/10.1351/pac199466051077)"
  ],
  "url": "https://mlchart.com/terminology/chemistry/leaving-group/"
}