Nuclear magnetic resonance/Catalogs/Magnetic nuclei

Nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) spectroscopy both exploit magnetically active atomic nuclei. That is, those elements with nuclear spin. In general, all atoms whose numbers of protons and numbers of neutroms are both even will not be magnetically active. When placed in a large superconducting magnet, these atomic nuclei will have multiple energy states. 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.

Element/Name	Atomic 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