Term: coupling constant (spin-spin), \(J\)
https://doi.org/10.1351/goldbook.C01383

Definition:
A quantitative measure for nuclear spin-spin, nuclear-electron (hyperfine coupling) and electron-electron (fine coupling in EPR) coupling in magnetic resonance spectroscopy. The 'indirect' or scalar NMR coupling constants are in a first approximation independent of the external magnetic field and are expressed in Hz.

Related Terms:
1) hyperfine coupling (http://doi.org/10.1351/goldbook.HT07052).
2) coupling (http://doi.org/10.1351/goldbook.C01025).
3) resonance (http://doi.org/10.1351/goldbook.R05326).
4) spectroscopy (http://doi.org/10.1351/goldbook.S05848).

Source: PAC, 1994, 66, 1077. 'Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)' on page 1101 (https://doi.org/10.1351/pac199466051077)

Citation: 'coupling constant (spin-spin), \(J\)' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. https://doi.org/10.1351/goldbook.C01383

License: The IUPAC Gold Book is licensed under Creative Commons Attribution-ShareAlike CC BY-SA 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/) for individual terms.

Disclaimer: The International Union of Pure and Applied Chemistry (IUPAC) is continuously reviewing and, where needed, updating terms in the Compendium of Chemical Terminology (the IUPAC Gold Book). Users of these terms are encouraged to include the version of a term with its use and to check regularly for updates to term definitions that you are using.