Iron(III) chloride hexahydrate (FeCl₃.6H₂O) has a low melting point (39°C) and in presence of graphite flakes the liquid salt spontaneously intercalates in the graphite sheets, thus generating a graphite intercalation compound (GIC). At higher temperatures, the graphite intercalation compound expands because of water evaporation and gaseous chlorine generation by the thermal decomposition of the anhydrous iron(III) salt. In particular, after dehydration, FeCl₃ decomposes to form chlorine (Cl₂) and iron(II) chloride (FeCl₂), which in turn disproportionates to generate elemental iron (Fe) and FeCl₃, up to a complete conversion of the salt to elemental iron. Since the resulting expanded graphite filaments contain elemental iron nanoparticles, this material shows ferromagnetic properties ^[1].