Usually Grignard reagents are written as RMgX .
In fact the magnesium ( II ) centre is tetrahedral when dissolved in Lewis basic solvents , as shown here for the bis - adduct of methylmagnesium chloride and THF .
Usually Grignard reagents are written as RMgX , but in fact the magnesium ( II ) centre is tetrahedral when dissolved in Lewis basic solvents , as shown here for the bis - adduct of methylmagnesium chloride and THF .