Write a note on halides of alkaline earth metal elements.

(N/A) Except for beryllium halides,all other halides of alkaline earth metals are ionic in nature. Beryllium halides are essentially covalent and soluble in organic solvents. Beryllium chloride has a chain structure in the solid state as shown below:
In the vapour phase $BeCl_{2}$ tends to form a chloro-bridged dimer which dissociates into the linear monomer at high temperatures of the order of $1200 \ K$.
The tendency to form halide hydrates gradually decreases (for example,$MgCl_{2} \cdot 8 H_{2} O$,$CaCl_{2} \cdot 6 H_{2} O$,$SrCl_{2} \cdot 6 H_{2} O$,$BaCl_{2} \cdot 2 H_{2} O$) down the group.
The dehydration of hydrated chlorides,bromides and iodides of $Ca$,$Sr$ and $Ba$ can be achieved on heating; however,the corresponding hydrated halides of $Be$ and $Mg$ on heating suffer hydrolysis. The fluorides are relatively less soluble than the chlorides owing to their high lattice energies.