Ring and double bond equivalent

{
  "id": "MLC-T-CHM-010358",
  "term": "Ring and double bond equivalent",
  "field": "Chemistry",
  "definition": "A value calculated from a molecular formula that indicates the degree of unsaturation in a molecule, corresponding to the number of rings plus the number of double bonds. For a molecule with the formula CxHyNzO, the ring and double bond equivalent is calculated as x minus y/2 plus z/2 plus 1. This calculation provides a quick method for deducing structural information from a chemical formula, particularly in mass spectrometry and nuclear magnetic resonance spectroscopy.",
  "subject": "Analytical Chemistry",
  "references": [
    "PAC, 2013, 85, 1515. 'Definitions of terms relating to mass spectrometry (IUPAC Recommendations 2013)' on page 1588 (https://doi.org/10.1351/PAC-REC-06-04-06)"
  ],
  "url": "https://mlchart.com/terminology/chemistry/ring-and-double-bond-equivalent/"
}