Wikipedia
Dimethylmagnesium
Dimethylmagnesium is an organomagnesium compound. Like other dialkylmagnesium compounds, it is prepared by adding at least one equivalent of dioxane to a solution of methylmagnesium halide:
2 CHMgX + dioxane (CH)Mg + MgX(dioxane)The complex of magnesium dihalide and dioxane precipitates as a solid, driving the Schlenk equilibrium to give the dialkylmagnesium compound, which remains in solution.
The structure of this compound has been determined by X-ray crystallography. The material is a polymer with tetrahedral magnesium centres, each surrounded by bridging methyl groups. The Mg-C distances are 224 pm.