Organomagnesium chemistry

Organomagnesium chemistry, a subfield of organometallic compounds, refers to the study of magnesium compounds that contains Mg-C bonds. Magnesium is the second element in group 2 (alkaline earth metals), and the ionic radius of Mg²⁺ is 86 pm, which is larger than Be²⁺ (59 pm) and smaller than the heavier alkaline earth metal dications (Ca²⁺ 114 pm, Sr²⁺ 132 pm, Ba²⁺ 149 pm), in accordance with periodic trends. Magnesium is less covalent compared to beryllium, and the radius is not large enough for accommodating large number of ligands compared to calcium, strontium and barium. Thus, organomagnesium compounds exhibit unique structure and reactivity in group 2.

From the perspective of applications, the Grignard reagents are the most important type of organomagnesium compound. They are widely used in synthetic chemistry, especially in organic synthesis, as a robust source of carbanion. Most other directions in organomagnesium chemistry are mainly of academic interest. Organomagnesium compounds are usually colorless. They are highly reactive toward air: water resulting on protonolysis, O₂ giving peroxides and alkoxides, and CO₂ givie carboxylates.