Quasi-molecular ion

{
  "id": "MLC-T-CHM-013460",
  "term": "Quasi-molecular ion",
  "field": "Chemistry",
  "definition": "An ion of mass close to that of the intact molecule in a soft ionization spectrum, either a protonated molecule, MH+, or an ion that has lost one hydrogen atom from a molecular ion, (M-H)+. It is seen in chemical ionization, electrospray and similar techniques where a true molecular ion is weak or absent. In the strict IUPAC sense it covers only these two kinds, so adduct ions such as ammonium or sodium attachments are excluded.",
  "subject": "Physical and Biophysical Chemistry",
  "references": [
    "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 1550 (https://doi.org/10.1351/pac199163101541)"
  ],
  "url": "https://mlchart.com/terminology/chemistry/quasi-molecular-ion/"
}