Aluminium chloride at higher temperatures exists as

Aluminum and chlorine combine to form aluminium chloride (${\mathrm{AlCl}}_3$). The solid is covalently bound and has a low melting and boiling point. At 178 ° C, it reaches its highest point. In contrast to more ionic halides like sodium chloride, molten ${\mathrm{AlCl}}_3$conducts electricity inefficiently. It has a six-coordinate layer lattice in the solid state.

${\mathrm{AlCl}}_3$adopts the "${\mathrm{YCl}}_3$" structure, which includes a layered structure made of ${\mathrm{Al}}^{3+}$ cubic tight packing. In contrast, the ${\mathrm{Al}}^{3+}$ centres in ${\mathrm{AlBr}}_3$ occupy nearby tetrahedral gaps in the tightly packed framework of $\mathrm{Br}$ions, giving this compound a more molecular structure. ${\mathrm{AlCl}}_3$melts to produce the vaporizable dimer ${\mathrm{Al}}_2{\mathrm{Cl}}_6$. This ${\mathrm{Al}}_2{\mathrm{Cl}}_6$dimer dissociates into trigonal planar ${\mathrm{AlCl}}_3$at higher temperatures.