Nuclei having the same resonance
frequency in nuclear magnetic resonancespectroscopy
and also identical spin-spin interactions with the nuclei of a neighbouring group
are magnetically equivalent. The spin-spin interaction between magnetically equivalent
nuclei does not appear, and thus has no effect on the multiplicity of the respective
NMR signals. Magnetically equivalent nuclei are necessarily also chemically equivalent,
but the reverse is not necessarily true.
PAC, 1994, 66, 1077
(Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994))
on page 1137
IUPAC. Compendium of Chemical Terminology, 2nd ed. (the "Gold Book"). Compiled by
A. D. McNaught and A. Wilkinson. Blackwell Scientific Publications, Oxford (1997).
XML on-line corrected version: http://goldbook.iupac.org (2006-) created by M. Nic,
J. Jirat, B. Kosata; updates compiled by A. Jenkins. ISBN 0-9678550-9-8. https://doi.org/10.1351/goldbook