Question

Write the general formula of Grignard reagent.

Answer 1

Grignard reagent involves an alkaline earth metal in its structure. The Grignard reagent has a nucleophilic alkyl or aryl group in its structure. It also involves elements from group-17 in the periodic table.

Complete step by step solution:
The Grignard reagent is an organic reagent which was found by scientist Victor Grignard.
-This reagent involves magnesium metal in its structure.
-Alongside magnesium metal, there is an alkyl or aryl group and a halogen atom bonded with it. So, this reagent is also called an organo-magnesium compound.
-The General formula of Grignard reagent is RMgX or R-MgX.
-Here, -R indicates the alkyl or aryl group.
-X can be any halogen atom-like chlorine (Cl), bromine (Br), or Iodine (I). Fluorine cannot be used in the Grignard reagent as it is hardly reactive when in the Grignard reagent.
-Here are some examples of the Grignard reagent.
$C{H_3}MgCl$ : Methyl magnesium chloride
$Ph - MgBr$ : Phenyl magnesium bromide
-The preparation of the Grignard reagent can be done by the reaction of an alkyl or aryl halide with magnesium metal in the ether as a solvent. So, we can write this reaction as
$R - X + Mg\xrightarrow{{Ether}}RMgX$
-The reaction shown here proceeds through a free radical mechanism. That means that the intermediates formed during the reaction are free radicals.

Thus, we can say that the formula for Grignard reagent is RMgX.

Note: Remember that anyone from the alkyl or aryl group can be there in the Grignard reagent. As Magnesium is a metal, it has a positive charge on it and the alkyl or aryl group bonded with the metal is nucleophilic in nature.