NMR Measurements and the Periodic Table

For quadrupolar nuclei, rapid pulsing can improve the signal-to-noise ratio. They are often most readily measured by vidde-line techniques however, as for example (84) and N (79). Many more wide-line measurements have been made of N, which is quadrupolar, than high-resolution measurements of N, which has spin but is expensive. The broadening increases with the nuclear quadrupole moment, which is small for (2.8 x 10 ), Li (4.6 x 10 ), and (—4 x 10 ), and fairly small, between 10 and 10 , for Be, B, N, S, C1, and C1 (the units are e x 10 cm, where e is the electronic charge) (20, 70). The broadening increases with asymmetry of the nuclear environment thus, the line width increases a thousand-fold from the relatively sharp line 

Natural Sensitivity at constant abimdance field relative to an equal (%) number of protons 

Paramagnetic broadening, due to unpaired electrons, is usually much greater than quadrupolar broadening, and the nuclear resonance 

23Na 3/2 26Mg 5/2 top right corner indicates that the nucleus has low sensitivity, 10-2 of that of an equal number of protons at constant field (see Table I).  

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