NMR of Less-Sensitive Spin — 1/2 Nuclei

摘要: Nearly every stable element has one or more magnetic isotopes which can, at least in principle, be observed by nuclear resonance. Only argon, among the naturally abundant representative and outer transition elements, possesses no isotope with a moment. Magnetic nuclei have properties that fall conveniently into two classes according to magnitude of spin. Those spins greater than one-half (shown hatched figure 1) nonspherical charge distributions give rise electric quadrupole moments. Resonances these are generally broad, often beyond practical limits detection, because highly efficient contribution relaxation rates. Chemically interesting information can favorable cases obtained from resonances however (1–6) although quadrupolar broadening tends obscure chemical shift differences spin-spin multiplet structure.