What is the exception to the octet rule with aluminum?

In some of its , aluminum violates the by having only six .

For example, aluminum chloride, AlCl₃, has only six around the Al atom.

However, AlCl₃ exists only at high temperatures. At ordinary temperatures, two molecules of AlCl₃ combine to form Al₂Cl₆. In this structure, both Al atoms do satisfy the octet rule.