Multinuclear NMR

Use our NMR service for our extensive experience of multinuclear NMR.

Select nucleus

NMR spectroscopy is possible with almost any element of the periodic table. Those that we have experience of are highlighted in the table below and can be selected for further information. If the nucleus you are interested in is in italics it means that we have no experience of it. All elements (except argon which has no stable NMR nucleus) are suitable for NMR and our NMR service will accept nuclei that we have no experience of. See below to acces our database of multinuclear NMR.

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Select from periodic table

Select the nucleus of interest from the periodic table or see below:

H                                       He
Li Be                        B  C  N  O  F  Ne
Na Mg                        Al Si P  S  Cl Ar
K  Ca Sc Ti V  Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
Rb Sr Y  Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I  Xe
Cs Ba La-Lu Hf Ta W  Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn
Fr Ra Ac-Lr Rf Db Sg Bh Hs Mt Ds Rg Cp              
       La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu
       Ac Th Pa U  Np Pu Am Cm Bk Cf Es Fm Md No Lr

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Select from list

from an alphabetical list of nuclei.

(Nuclei in parentheses are less desirable that other isotopes of the same element.) We have no experience of nulei in italics.

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Comparison of nuclear properties

Nuclei vary in ease of observation. There are three main factors that affect the ease of observing nuclei: receptivity (sensitivity), line-width and chemical shift dispersion. It is advisable to take these into account before tackling a nucleus that you are unfamiliar with. Often there is more than one NMR nucleus for an element. Sometimes, each isomer has its own advantages (e.g., nitrogen, where 14N is more sensitive at natural abundance but 15N yields much narrower signals because it is not quadrupolar) and sometimes one isotope is better on all counts (as is the case for the stable nuclei of hydrogen where 1H is more sensitive and yields narrower signals than 2H. Therefore 1H is the isotope of choice unless studying specific isotopic substitution).

Different nuclei have different receptivities, 1H being the most sensitive stable nucleus with 19F following closely behind. The effective receptivity is a product of the nucleus' inherent receptivity and its natural abundance. For example 3He has an inherent receptivity 0.44 times that of proton but has such a low natural abundance that it is all but unobservable; however, when enriched it can be observed easily.

The line-widths of spin-½ nuclei are generally small unless affected by paramagnetism or anisotropy. Heavier nuclei such as 199Hg are more prone to anisotropic tumbling than lighter nuclei and the problem gets worse for larger molecules at higher magnetic fields. Broad signals are usually an issue for quadrupolar nuclei (spin > ½) and are broader for larger linewidth parameter, molecular size, asymmetry at the nucleus and magnetic field of the spectrometer. In many cases, the line-width is too broad to be detected with a high-resolution spectrometer, for example, the 127I line-width of aqueous KI in a 400 MHz spectrometer is of the order of 2 kHz but for the larger and less symmetric iodobenzene it is of the order of 10 MHz, much too broad to be observed by a high-resolution spectrometer and more than an order of magnitude wider than its chemical shift range.

Chemical shift dispersion varies widely between nuclei as a function of both electronic and chemical properties with some tendency to larger dispersions for heavier nuclei. The chemical shift range varies from around 10 ppm for hydrogen to 20000 ppm for cobalt. When the chemical shift range is very large, the chemical shift is extremely sensitive to environmental parameters and the signals may be broadened by temperature gradients across the sample. The chemical shift ranges for different isotopes of the same element are almost identical.

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