Bridgehead atom

{
  "id": "MLC-T-CHM-001501",
  "term": "Bridgehead atom",
  "field": "Chemistry",
  "definition": "An atom common to two or more rings of a polycyclic molecule that is separated from another such atom by bridges that all contain at least one atom, as carbons 1 and 4 of norbornane, which are joined by bridges of two, two, and one carbons. Bridgehead carbons in saturated frameworks are usually tertiary, bearing one hydrogen, not quaternary. A double bond at a bridgehead is restricted by Bredt's rule in small rings.",
  "synonyms": [
    "bridgehead"
  ],
  "subject": "Organic and Biomolecular Chemistry",
  "references": [
    "PAC, 2022, 94, 353. 'Glossary of terms used in physical organic chemistry (IUPAC Recommendations 2021)' on page 374 (https://doi.org/10.1515/pac-2018-1010)"
  ],
  "url": "https://mlchart.com/terminology/chemistry/bridgehead-atom/"
}