Nuclear magnetic resonance/Catalogs/Magnetic nuclei: Difference between revisions
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Revision as of 16:07, 19 October 2007
Nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) spectroscopy both exploit magnetically active atomic nuclei. That is, those elements with non-zero nuclear spin (I). Although nuclear spin (or angular momentum) is listed as a single variable, it is the sum of the individual angular momenta of all protons and neutrons. In general, all atoms whose numbers of protons and numbers of neutrons are not both even will be magnetically active because the spins of the individual nucleons do not cancel each other out completely. When placed in a very strong magnet these atomic nuclei will have 2I+1 energy states whose energy differences are dependent on the strength of the magnetic field. In the simplest case where the nuclear spin = 1/2, the spin can be aligned with or against the field. By exciting the nuclei with energy, typically in the radio frequency range of the electromagnetic spectrum, the lowest energy state is excited to a higher energy state. A signal, call the free induction decay (FID) is then measured as the excited state relaxes back to the lower energy state. The table below lists the isotope(s) of elements that have nuclear spin and therefore may be used in NMR or MRI spectroscopy. Only three chemical elements with atomic numbers less than Bismuth (Z=81) do not have magnetically active isotopes: Argon, Cesium and Promethium.
NOTE: All nuclear spins are positive. Negative spin values shown below indicate that the gyromagnetic ratio has a negative value, which means that the atomic magnetic moment and the nuclear spin are aligned antiparallel to each other. For nuclear magnetic resonance spectroscopists designing complex excitation schemes, it is convenient to think of such atoms as having negative nuclear spins because, compared to atoms with positive gyromagnetic ratios, the nuclei align in the opposite direction and therefore also precess (rotate) about the magnetic field in the opposite direction. (No matter what sign the spin value has they respond to a strong magnetic field one in the direction Z and the other in the direction -Z. Important is to note they respond likewise only the direction differs by 180˚in the direction of the applied magnetic field.)
| Element/Name | Isotope Symbol | Nuclear Spin | Sensitivity vs. 1H |
|---|---|---|---|
| Hydrogen | 1H | 1/2 | 1.000000 |
| Deuterium | 2H or D | 1 | 1.44 e-6 |
| Tritium | 3H | 1/2 | - |
| Helium-3 | 3He | -1/2 | - |
| Lithium-6 | 6Li | 1 | 0.000628 |
| Lithium-7 | 7Li | 3/2 | 0.270175 |
| Beryllium-9 | 9Be | -3/2 | 0.013825 |
| Boron-10 | 10B | 3 | 0.00386 |
| Boron-11 | 11B | 3/2 | 0.132281 |
| Carbon-13 | 13C | 1/2 | 0.000175 |
| Nitrogen-14 | 14N | 1 | 0.000998 |
| Nitrogen-15 | 15N | -1/2 | 3.84E-06 |
| Oxygen-17 | 17O | -5/2 | 1.07E-05 |
| Fluorine-19 | 19F | 1/2 | 0.829825 |
| Neon-21 | 21Ne | -3/2 | 6.3E-06 |
| Sodium-23 | 23Na | 3/2 | 0.092105 |
| Magnesium-25 | 25Mg | -5/2 | 0.00027 |
| Aluminum-27 | 27Al | 5/2 | 0.205263 |
| Silicon-29 | 29Si | -1/2 | 0.000367 |
| Phosphorus-31 | 31P | 1/2 | 0.06614 |
| Sulfur-33 | 33S | 3/2 | 1.71E-05 |
| Chlorine-33 | 33Cl | 3/2 | 0.003544 |
| Chlorine-37 | 37Cl | 3/2 | 0.000661 |
| Potassium-39 | 39K | 3/2 | 0.000472 |
| Potassium-41 | 41K | 3/2 | 5.75E-06 |
| Calcium-43 | 43K | -7/2 | 9.25E-06 |
| Scandium-45 | 45Sc | 7/2 | 0.3 |
| Titanium-47 | 47Ti | -5/2 | 0.00015 |
| Titanium-49 | 49Ti | -7/2 | 0.00021 |
| Vanadium-50 | 50V | 6 | 0.00013 |
| Vanadium-51 | 51V | 7/2 | 0.37895 |
| Chromium-53 | 53Cr | -3/2 | 8.6E-05 |
| Manganese-55 | 55Mn | 5/2 | 0.174386 |
| Iron-57 | 57Fe | 1/2 | 7.37E-07 |
| Cobolt-59 | 59Co | 7/2 | 0.275439 |
| Nickel-61 | 61Ni | -3/2 | 4.21E-05 |
| Copper-63 | 63Cu | 3/2 | 0.064035 |
| Copper-65 | 65Cu | 3/2 | 0.035263 |
| Zinc-67 | 67Zn | 5/2 | 0.000117 |
| Gallium-69 | 69Ga | 3/2 | 0.041579 |
| Gallium-71 | 71Ga | 3/2 | 0.055965 |
| Germanium-73 | 73Ge | -9/2 | 0.000108 |
| Arsenic-75 | 75As | 3/2 | 0.025088 |
| Selenium-77 | 77Se | 1/2 | 0.000523 |
| Bromine-79 | 79Br | 3/2 | 0.039649 |
| Bromine-81 | 81Br | 3/2 | 0.048596 |
| Krypton-83 | 83Kr | -9/2 | 0.000216 |
| Rubidium-85 | 85Rb | 5/2 | 0.007544 |
| Rubidium-87 | 87Rb | 3/2 | 0.048596 |
| Strontium-87 | 87Sr | -9/2 | 0.000188 |
| Yttrium-89 | 89Y | -1/2 | 0.00012 |
| Zirconium-91 | 91Zr | -5/2 | 0.00106 |
| Niobium-93 | 93Nb | 9/2 | 0.4807 |
| Molybdenum-95 | 95Mo | 5/2 | 0.00051 |
| Molybdenum-97 | 97Mo | -5/2 | 0.00032 |
| Technetium-99 | 99Tc | 9/2 | 0.374386 |
| Ruthenium-99 | 99Ru | -5/2 | 0.000146 |
| Ruthenium-101 | 101Ru | -5/2 | 0.000274 |
| Rhodium-103 | 103Rh | -1/2 | 3.11E-05 |
| Paladium-105 | 105Pd | -5/2 | 0.000247 |
| Silver-107 | 107Ag | -1/2 | 3.245E-05 |
| Silver-109 | 109Ag | -1/2 | 4.84E-05 |
| Cadmium-111 | 111Cd | -1/2 | 0.001216 |
| Cadmium-113 | 113Cd | -1/2 | 0.001313 |
| Indium-113 | 113In | 9/2 | 0.014702 |
| Indium-115 | 113In | 9/2 | 0.331579 |
| Tin-117 | 117Sn | -1/2 | 0.003428 |
| Tin-119 | 119Sn | -1/2 | 0.004421 |
| Antimony-121 | 121Sb | 5/2 | 0.091228 |
| Antimony-123 | 123Sb | 7/2 | 0.019474 |
| Tellurium-123 | 123Te | -1/2 | 0.000156 |
| Tellurium-125 | 125Te | 5/2 | 0.002193 |
| Iodine-127 | 127I | 5/2 | 0.092982 |
| Xenon-129 | 129Xe | -1/2 | 0.005579 |
| Xenon-131 | 131Xe | 3/2 | 0.000581 |
| Cesium-133 | 133Cs | 7/2 | 0.047193 |
| Barium-135 | 135Ba | 3/2 | 0.000316 |
| Barium-137 | 137Ba | 3/2 | 0.000774 |
| Lanthinum-139 | 139La | 7/2 | 0.05895 |
| Praseodymium-141 | 141Pr | 5/2 | 0.29825 |
| Neodymium-143 | 143Nd | -7/2 | 0.0004 |
| Neodymium-145 | 145Nd | -7/2 | 6.5E-05 |
| Samarium-147 | 147Sm | -7/2 | 2.21E-05 |
| Samarium-149 | 147Sm | -7/2 | 0.000104 |
| Europium-151 | 151Eu | 5/2 | 0.084211 |
| Europium-153 | 153Eu | 5/2 | 0.007895 |
| Gadolidium-155 | 155Gd | -3/2 | 0.03.51E-05 |
| Gadolidium-157 | 157Gd | -3/2 | 8.42E-05 |
| Terbium-159 | 159Tb | 3/2 | 0.057895 |
| Dysprosium-161 | 161Dy | -5/2 | 7.95E-05 |
| Dysprosium-163 | 163Dy | 5/2 | 0.000281 |
| Holmium-165 | 165Ho | 7/2 | 0.175439 |
| Erbiumm-167 | 167Er | -7/2 | 0.000116 |
| Thulium-169 | 169Tm | -1/2 | 0.000561 |
| Ytterbium-171 | 171Yb | 1/2 | 0.000711 |
| Ytterbium-173 | 173Yb | -5/2 | 0.0002 |
| Lutetium-175 | 175Lu | 7/2 | 0.027386 |
| Lutetium-176 | 176Lu | 7 | 0.000902 |
| Halfnium-177 | 177Hf | 7/2 | 0.00015 |
| Halfnium-179 | 179Hf | -9/2 | 4.7E-05 |
| Tantalum-181 | 181Ta | 7/2 | 0.03579 |
| Tungsten-183 | 183W | 1/2 | 1E-05 |
| Rhenium-185 | 185Re | 5/2 | 0.049123 |
| Rhenium-187 | 187Re | 5/2 | 0.085965 |
| Osmium-187 | 187Os | 1/2 | 2E-07 |
| Osmium-189 | 189Os | 3/2 | 0.000374 |
| Iridium-191 | 191Ir | 3/2 | 4E-06 |
| Iridium-193 | 193Ir | 3/2 | 8.77E-06 |
| Platinum-195 | 195Pt | 1/2 | 0.003351 |
| Gold-197 | 197Au | 3/2 | 1.05E-05 |
| Mercury-199 | 199Hg | 1/2 | 0.000951 |
| Mercury-201 | 201Hg | -3/2 | 0.000189 |
| Titanium-203 | 203Ti | 1/2 | 0.050702 |
| Titanium-205 | 205Ti | 1/2 | 0.134912 |
| Lead-207 | 207Pb | 1/2 | 0.00207 |
| Bismuth-209 | 209Bi | 9/2 | 0.136316 |
| Uranium-235 | 235Ur | -7/2 | - |
| Plutonium-239 | 239Pu | 1/2 | - |
| Americium-243 | 243Am | 5/2 | - |
Further Reading
References
Different forms of "NMR Periodic Tables" can be found at:
http://nmr.magnet.fsu.edu/resources/nuclei/table.htm
http://www.chem.tamu.edu/services/NMR/periodic/
http://www.eclipse.net/~numare/co.htm
This one is color coded by spin values: http://www.bruker-nmr.de/guide/eNMR/chem/NMRnuclei.html