Molecular ion

{
  "id": "MLC-T-CHM-007501",
  "term": "Molecular ion",
  "field": "Chemistry",
  "definition": "An ion formed by removing electrons from a molecule, giving a positive ion, or adding electrons to it, giving a negative ion, with no fragmentation of its structure. Its mass is calculated from the most abundant isotope of every element present, adjusted for the electrons removed or added. A protonated molecule is not a molecular ion, because it differs from the neutral molecule by a whole proton and not by electrons.",
  "synonyms": [
    "molecular anion",
    "molecular cation"
  ],
  "subject": "Physical and Biophysical Chemistry",
  "see_also": [
    "fragmentation",
    "isotopes",
    "unified atomic mass unit"
  ],
  "references": [
    "Orange Book, 2nd ed., p. 205 (https://media.iupac.org/publications/analytical_compendium/)",
    "PAC, 1991, 63, 1541. 'Recommendations for nomenclature and symbolism for mass spectroscopy (including an appendix of terms used in vacuum technology). (Recommendations 1991)' on page 1549 (https://doi.org/10.1351/pac199163101541)"
  ],
  "url": "https://mlchart.com/terminology/chemistry/molecular-ion/"
}