Transient species

{
  "id": "MLC-T-CHM-012226",
  "term": "Transient species",
  "field": "Chemistry",
  "definition": "A short-lived reaction intermediate, such as a radical, carbene, carbocation or excited state, whose lifetime is too short for it to be isolated or observed by ordinary methods. What counts as transient depends on the experimental time scale and detection technique, so the same species can be transient in one experiment and persistent in another. Flash photolysis and pulse radiolysis detect transients with lifetimes from nanoseconds to milliseconds.",
  "synonyms": [
    "transient chemical species"
  ],
  "subject": "Organic and Biomolecular Chemistry",
  "see_also": [
    "intermediate",
    "persistent",
    "unstable"
  ],
  "references": [
    "PAC, 1994, 66, 1077. 'Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)' on page 1174 (https://doi.org/10.1351/pac199466051077)"
  ],
  "url": "https://mlchart.com/terminology/chemistry/transient-species/"
}