Radical pair

{
  "id": "MLC-T-CHM-009854",
  "term": "Radical pair",
  "field": "Chemistry",
  "definition": "A molecular entity comprising two radicals in close proximity, held together within a solvent cage or as part of the same molecule. The unpaired electron spins of the two radicals are coupled, resulting in either a singlet state with antiparallel spins or a triplet state with parallel spins. The interconversion between these spin states, which dictates reaction outcomes like recombination or escape, is sensitive to external magnetic fields, a phenomenon observable through chemically induced dynamic nuclear polarization (CIDNP).",
  "synonyms": [
    "geminate pair"
  ],
  "subject": "Organic and Biomolecular Chemistry",
  "see_also": [
    "chemically induced dynamic nuclear polarization",
    "cage",
    "decomposition",
    "diffusion",
    "geminate recombination",
    "radical",
    "molecularity"
  ],
  "references": [
    "PAC, 1994, 66, 1077. 'Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)' on page 1156 (https://doi.org/10.1351/pac199466051077)",
    "PAC, 1995, 67, 1307. 'Glossary of class names of organic compounds and reactivity intermediates based on structure (IUPAC Recommendations 1995)' on page 1363 (https://doi.org/10.1351/pac199567081307)",
    "PAC, 1996, 68, 2223. 'Glossary of terms used in photochemistry (IUPAC Recommendations 1996)' on page 2270 (https://doi.org/10.1351/pac199668122223)"
  ],
  "url": "https://mlchart.com/terminology/chemistry/radical-pair/"
}