
Dimethylmagnesium

Dimethylmagnesium is an organomagnesium compound. It is a white pyrophoric solid.
Preparation.
Like other dialkylmagnesium compounds, it is prepared by adding at least one equivalent of dioxane to a solution of methylmagnesium halide:
Addition of 0.5 molar equivalents of 1,4-dioxane causes precipitation of MgX2 as an insoluble dioxane-adduct, driving the Schlenk equilibrium to (CH3)2Mg.
It can also be prepared by treating calcium, magnesium and methyl iodide in diethyl ether or by combining dimethyl mercury and magnesium.
Properties.
The structure of this compound has been determined by X-ray crystallography. The material is a polymer with the same connectivity as silicon disulfide, featuring tetrahedral magnesium centres, each surrounded by bridging methyl groups. The Mg-C distances are 224 pm. Dimethylberylium adopts the same structure.