Hard base

{
  "id": "MLC-T-CHM-013143",
  "term": "Hard base",
  "field": "Chemistry",
  "definition": "A Lewis base characterized by a donor atom of high electronegativity, low polarizability, and high resistance to oxidation. These bases hold their valence electrons tightly and have highest occupied molecular orbitals of low energy. Common examples of hard bases include H2O, OH−, F−, and NH3, which form strong interactions with hard acids.",
  "subject": "Organic and Biomolecular Chemistry",
  "see_also": [
    "Lewis base",
    "hard acid",
    "polarizability"
  ],
  "references": [
    "PAC, 1994, 66, 1077. 'Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)' on page 1120 (https://doi.org/10.1351/pac199466051077)"
  ],
  "url": "https://mlchart.com/terminology/chemistry/hard-base/"
}