The chlorides of both beryllium and aluminium have Cl– bridged chloride structure in vapour phase. Both the chlorides are soluble in organic solvents and are strong Lewis acids. They are used as Friedel Craft catalysts.
Be2Cl4 is lewis acid and Al2Cl6 has complete octet.
Be and Al are amphoteric metals therefore dissolve in acid as well as alkaline solution and form beryllate and aluminate ions in excess alkali.
Beryllium hydroxide dissolves in excess of alkali to give a beryllate ion,[Be(OH)4]2– just as aluminium hydroxide gives aluminate ion, [Al(H2O)2(OH)4]−