Write a note on Grignard Reagent.

(N/A) Most organic chlorides,bromides,and iodides react with certain metals to form compounds containing carbon-metal bonds,known as organometallic compounds.
Victor Grignard discovered an important class of organometallic compounds known as alkyl magnesium halides $(RMgX)$,which are referred to as Grignard reagents.
Grignard reagents are prepared by the reaction of haloalkanes with magnesium metal in the presence of dry ether:
$CH_3CH_2Br + Mg \xrightarrow{\text{dry ether}} CH_3CH_2MgBr$
In a Grignard reagent,the carbon-magnesium bond is covalent but highly polar,with the carbon atom pulling electrons from the electropositive magnesium atom. The magnesium-halogen bond is essentially ionic. The structure is represented as $R^{\delta-} - Mg^{2+}X^{\delta-}$.
Grignard reagents are highly reactive toward moisture and react with water to form hydrocarbons:
$RMgX + H_2O \longrightarrow RH + Mg(OH)X$
Therefore,it is necessary to avoid even traces of moisture,which is why the reaction is carried out in anhydrous (dry) ether. This is a useful method for converting alkyl halides into hydrocarbons.