Dimethylmagnesium is an organomagnesium compound with the

chemical formula A chemical formula is a way of presenting information about the chemical proportions of atoms that constitute a particular chemical compound or molecule, using chemical element symbols, numbers, and sometimes also other symbols, such as pare ...

. It is a white

pyrophoric A substance is pyrophoric (from , , 'fire-bearing') if it ignites spontaneously in air at or below (for gases) or within 5 minutes after coming into contact with air (for liquids and solids). Examples are organolithium compounds and triethylb ...

solid. Dimethylmagnesium is used in the synthesis of organometallic compounds.

Preparation

Like other dialkylmagnesium compounds, dimethylmagnesium is prepared by adding dioxane to a solution of methylmagnesium halide: : In such procedures, the dimethylmagnesium exists as the ether adduct, not the polymer. Addition of 1,4-dioxane causes precipitation of solid , a

coordination polymer Coordination may refer to: * Coordination (linguistics), a compound grammatical construction * Coordination complex, consisting of a central atom or ion and a surrounding array of bound molecules or ions ** A chemical reaction to form a coordinat ...

. This precipitation drives the

Schlenk equilibrium The Schlenk equilibrium, named after its discoverer Wilhelm Schlenk, is a chemical equilibrium taking place in solutions of Grignard reagents and Hauser bases :2 RMgX MgX2 + MgR2 The process described is an equilibrium between two equivalents o ...

toward . Related methods have been applied to other dialkylmagnesium compounds. Dimethylmagnesium can also be prepared by combining dimethylmercury and magnesium.

Calcium Calcium is a chemical element; it has symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to it ...

metal,

magnesium Magnesium is a chemical element; it has Symbol (chemistry), symbol Mg and atomic number 12. It is a shiny gray metal having a low density, low melting point and high chemical reactivity. Like the other alkaline earth metals (group 2 ...

metal and

methyl iodide Iodomethane, also called methyl iodide, and commonly abbreviated "MeI", is the chemical compound with the formula CH3I. It is a dense, colorless, volatile liquid. In terms of chemical structure, it is related to methane by replacement of one h ...

reacts in

diethyl ether Diethyl ether, or simply ether, is an organic compound with the chemical formula , sometimes abbreviated as . It is a colourless, highly Volatility (chemistry), volatile, sweet-smelling ("ethereal odour"), extremely flammable liquid. It belongs ...

to produce dimethylmagnesium. :

Properties

The structure of this compound has been determined by

X-ray crystallography X-ray crystallography is the experimental science of determining the atomic and molecular structure of a crystal, in which the crystalline structure causes a beam of incident X-rays to Diffraction, diffract in specific directions. By measuring th ...

. The material is a polymer with the same connectivity as

silicon disulfide Silicon disulfide is the inorganic compound with the formula Si S2. Like silicon dioxide, this material is polymeric, but it adopts a 1-dimensional structure quite different from the usual forms of SiO2. Synthesis, structure, and properties Th ...

, featuring tetrahedral magnesium centres, each surrounded by bridging methyl groups. The Mg-C distances are 224 pm.

Related compounds

The linear chain structure seen for dimethylmagnesium is also observed for diethylmagnesium and dimethylberyllium. Di(''tert''-butyl)magnesium is however a dimer.

References

{{Reflist Organomagnesium compounds Pyrophoric materials Polymers