'A' value

{
  "id": "MLC-T-CHM-000027",
  "term": "'A' value",
  "field": "Chemistry",
  "definition": "A measure of the conformational preference of a substituent on a cyclohexane ring, representing the difference in Gibbs free energy between the axial and equatorial positions. A larger 'A' value indicates a stronger preference for the equatorial position due to steric hindrance in the axial orientation. These values are typically determined experimentally using nuclear magnetic resonance spectroscopy or computational methods.",
  "synonyms": [
    "Winstein-Holness A value"
  ],
  "subject": "Organic and Biomolecular Chemistry",
  "see_also": [
    "equatorial",
    "equilibration"
  ],
  "references": [
    "PAC, 1994, 66, 1077. 'Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)' on page 1087 (https://doi.org/10.1351/pac199466051077)"
  ],
  "url": "https://mlchart.com/terminology/chemistry/a-value/"
}