Lanthanide chlorides

Lanthanide chlorides are a group of chemical compounds that can form between a lanthanide element (from lanthanum to lutetium) and chlorine. The lanthanides in these compounds are usually in the +2 and +3 oxidation states, although compounds with lanthanides in lower oxidation states exist.

Lanthanide dichlorides
Divalent chlorides are formed by neodymium, samarium, europium, dysprosium, thulium and ytterbium. They can be prepared by reducing the trivalent chloride with lithium metal/naphthalene in tetrahydrofuran:


 * LnCl3 + Li → LnCl2 + LiCl (Ln=Nd,Sm,Eu)

Reducing the chloride with the metal or hydrogen is also possible:


 * 2 LnCl3 + Ln → 3 LnCl2 (Ln=Nd,Sm,Eu?,Dy,Tm,Yb)


 * 2 LnCl3 + H2 → 2 LnCl2 + 2 HCl (Ln=Nd,Sm,Eu,Dy,Tm,Yb)

Lanthanide trichlorides
The lanthanide trichlorides can generally be prepared by dissolving the oxide or carbonate with hydrochloric acid. They are produced commercially by carbothermic reaction of the oxide. To produce the anhydrous forms of these trichlorides, the ammonium chloride route is taken. The anhydrous lanthanide trichlorides have high melting points and are generally pale colored.