Cumulenes

{
  "id": "MLC-T-CHM-002787",
  "term": "Cumulenes",
  "field": "Chemistry",
  "definition": "Hydrocarbons, and by extension substituted derivatives, that contain three or more cumulative double bonds in a row, as in butatriene, R2C=C=C=CR2. Compounds with only two cumulative double bonds are called allenes instead. In cumulenes with an odd number of double bonds the end substituents lie in one plane, giving cis and trans isomers, whereas those with an even number of double bonds can be axially chiral.",
  "subject": "Organic and Biomolecular Chemistry",
  "see_also": [
    "hydrocarbons",
    "allenes",
    "cumulative double bonds",
    "heterocumulenes"
  ],
  "references": [
    "PAC, 1995, 67, 1307. 'Glossary of class names of organic compounds and reactivity intermediates based on structure (IUPAC Recommendations 1995)' on page 1329 (https://doi.org/10.1351/pac199567081307)"
  ],
  "url": "https://mlchart.com/terminology/chemistry/cumulenes/"
}