Title: spin
Long Title: IUPAC Gold Book - spin
DOI: 10.1351/goldbook.08418
Status: current

Definition
Intrinsic angular momentum of a nucleus (or other sub-atomic particle).

Notes
1) The magnitude of nuclear spin is \((h/2\pi)\sqrt{I(I + 1)}\) where \(I\) is the spin quantum number and \(h\) is the Planck constant.
2) In nuclear magnetic resonance spectroscopy, only nuclei with spin \(I \gt 0\) are observable.
3) The spin of a nucleus is dependent on the numbers and alignments of the spins of its individual protons and neutrons.
4) Nuclei with a spin of \(½\) generate the simplest nuclear magnetic resonance spectra and are thus the most commonly studied.

Related Terms
- nuclear magnetic resonance spectra: https://goldbook.iupac.org//terms/view/08384
- nuclear magnetic resonance spectroscopy: https://goldbook.iupac.org//terms/view/08218

Source
- PAC, 2021, 93, 647. 'Glossary of methods and terms used in analytical spectroscopy (IUPAC Recommendations 2019)' on page 705 (https://doi.org/10.1515/pac-2019-0203)

Other Outputs
- html: https://goldbook.iupac.org/terms/view/08418/html
- json: https://goldbook.iupac.org/terms/view/08418/json
- xml: https://goldbook.iupac.org/terms/view/08418/xml

Citation: Citation: 'spin' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. 10.1351/goldbook.08418
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Accessed: 2026-05-28T12:54:05+00:00