Table 5. Complete List of Stable Noble Gas Isotopes with Nuclear Spin I > 0a.
| Isotope | Nuclear spin I | Natural abundance, % | NMR frequency at 3 T for pure gas interpolated to zero density, MHz | Thermal equilibrium polarization at 3 T and 300 K | Nuclear electric quadrupole moment (Q)/10–28 m2 |
|---|---|---|---|---|---|
| 3He | 1/2 | <2 × 10–4 | 97.30 | 7.78 × 10–6 | – |
| 21Ne | 3/2 | 0.27 | 10.08 | 1.34 × 10–6 | 0.102 |
| 83Kr | 9/2 | 11.49 | 4.915 | 1.44 × 10–6 | 0.259 |
| 129Xe | 1/2 | 26.44 | 35.33 | 2.83 × 10–6 | – |
| 131Xe | 3/2 | 21.18 | 10.47 | 1.40 × 10–6 | –0.114 |
a
The noble gas resonance frequencies are for the pure gas (oxidation state 0), interpolated to zero gas pressure as the resonance frequency is pressure-dependent, in particular for Xe and Kr (note that some manufactures of spectrometers use XeOF4 for frequency reference, leading to more than 5000 ppm higher resonance frequencies than that of the gas). The thermal equilibrium spin polarization ptherm for 3 T magnetic field strength and 300 K is provided based on eq 9 (i.e., based on a theoretical maximum polarization of p = 1).