Mass defect

{
  "id": "MLC-T-CHM-006974",
  "term": "Mass defect",
  "field": "Chemistry",
  "definition": "The difference between the exact mass of an atom or molecule and its nominal mass, which is the integer mass of its most abundant isotope. It arises from the binding energy of the nucleus and the slight variations in isotopic masses. In mass spectrometry, mass defect is used to distinguish between compounds with the same nominal mass but different elemental compositions, aiding in formula determination.",
  "subject": "Analytical Chemistry",
  "see_also": [
    "monoisotopic mass"
  ],
  "references": [
    "PAC, 2013, 85, 1515. 'Definitions of terms relating to mass spectrometry (IUPAC Recommendations 2013)' on page 1563 (https://doi.org/10.1351/PAC-REC-06-04-06)"
  ],
  "url": "https://mlchart.com/terminology/chemistry/mass-defect/"
}