Safety note: Some of the materials mentioned here are very dangerous. Ask a qualified chemist for advice before handling them. Qualified chemists should check the relevant safety literature before handling or giving advice about unfamiliar substances. NMR solvents are toxic and most are flammable. Specifically, magnesium salts can be toxic in large doses.

²⁵Magnesium NMR

²⁵Magnesium (²⁵Mg) is a low sensitivity nucleus that yields slightly broad lines over a moderate chemical shift range. ²⁵Mg is a spin 5/2 nucleus and is therefore quadrupolar. As a result, the signal width increases with asymmetry of the environment with relatively narrow lines in symmetrical environments (fig. 1) but broad lines in asymmetric ones such as Grignyard reagents. The main use of magnesium NMR is to measure its relaxation rate in order to detect binding to biomolecules. The chemical shift of inorganic magnesium is quite solvent dependent but there is little information available about magnesium chemical shifts (fig. 2).

Fig. 1. ²⁵Na-NMR spectrum of MgCl₂ in D₂O

Fig. 2. Chemical shift ranges for ²⁵Mg NMR

Properties of ²⁵Mg

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