Magnetic Properties of Most Common Nuclei
1H and 13C aren't the only nuclei susceptible to NMR experiments. A number of different nuclei can also be detected, although the use of such techniques is generally rare due to small relative sensitivities in NMR experiments (compared to 1H) of the nuclei in question, the other factor for rare use being their slender representation in nature/organic compounds.
| Isotope | Occurrence in nature (%) |
spin number l | Magnetic moment μ |
Electric quadrupole moment (e×10−24 cm2) |
Operating frequency at 7 T (MHz) |
Relative sensitivity |
|---|---|---|---|---|---|---|
| 1H | 99.984 | 1/2 | 2.79628 | 300.13 | 1 | |
| 2H | 0.016 | 1 | 0.85739 | 2.8 x 10−3 | 46.07 | 0.0964 |
| 10B | 18.8 | 3 | 1.8005 | 7.4 x 10−2 | 32.25 | 0.0199 |
| 11B | 81.2 | 3/2 | 2.6880 | 2.6 x 10−2 | 96.29 | 0.165 |
| 12C | 98.9 | 0 | ||||
| 13C | 1.1 | 1/2 | 0.70220 | 75.47 | 0.0159 | |
| 14N | 99.64 | 1 | 0.40358 | 7.1 x 10−2 | 21.68 | 0.00101 |
| 15N | 0.37 | 1/2 | −0.28304 | 30.41 | 0.00104 | |
| 16O | 99.76 | 0 | ||||
| 17O | 0.0317 | 5/2 | −1.8930 | −4.0 x 10−3 | 40.69 | 0.0291 |
| 19F | 100 | 1/2 | 2.6273 | 282.40 | 0.834 | |
| 28Si | 92.28 | 0 | ||||
| 29Si | 4.70 | 1/2 | −0.55548 | 59.63 | 0.0785 | |
| 31P | 100 | 1/2 | 1.1205 | 121.49 | 0.0664 | |
| 35Cl | 75.4 | 3/2 | 0.92091 | −7.9 x 10−2 | 29.41 | 0.0047 |
| 37Cl | 24.6 | 3/2 | 0.68330 | −6.2 x 10−2 | 24.48 | 0.0027 |
| Magnetic properties of common nuclei | ||||||
1H, 13C, 15N, 19F and 31P are the five nuclei that have the greatest importance in NMR experiments:
- 1H because of high sensitivity and vast occurrence in organic compounds
- 13C because of being the key component of all organic compounds despite occurring at a low abundance (1.1%) compared to the major isotope of carbon 12C, which has a spin of 0 and therefore is NMR inactive.
- 15N because of being a key component of important biomolecules such as proteins and DNA
- 19F because of high relative sensitivity
- 31P because of frequent occurrence in organic compounds and moderate relative sensitivity
Read more about this topic: Chemical Shift
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