Indicated hydrogen

{
  "id": "MLC-T-CHM-005768",
  "term": "Indicated hydrogen",
  "field": "Chemistry",
  "definition": "A hydrogen atom explicitly shown in the name of a heterocyclic compound to specify the position of saturation in an otherwise unsaturated ring system. This is necessary when the maximum number of non-cumulative double bonds is not present. The position of the indicated hydrogen is typically denoted by an italicized 'H' followed by its locant, such as 1H-pyrrole.",
  "synonyms": [
    "added hydrogen"
  ],
  "subject": "Organic and Biomolecular Chemistry",
  "see_also": [
    "cumulative double bonds"
  ],
  "references": [
    "Blue Book Guide, p. 34 (https://doi.org/10.1351/pac199971071327)"
  ],
  "url": "https://mlchart.com/terminology/chemistry/indicated-hydrogen/"
}