Lanthanide chlorides are a group of chemical compounds that can form between a lanthanide element (from

lanthanum Lanthanum is a chemical element with the symbol La and atomic number 57. It is a soft, ductile, silvery-white metal that tarnishes slowly when exposed to air. It is the eponym of the lanthanide series, a group of 15 similar elements between lantha ...

to lutetium) and

chlorine Chlorine is a chemical element with the Symbol (chemistry), symbol Cl and atomic number 17. The second-lightest of the halogens, it appears between fluorine and bromine in the periodic table and its properties are mostly intermediate betwee ...

. The lanthanides in these compounds are usually in the +2 and +3

oxidation state In chemistry, the oxidation state, or oxidation number, is the hypothetical charge of an atom if all of its bonds to different atoms were fully ionic. It describes the degree of oxidation (loss of electrons) of an atom in a chemical compound. C ...

s, although compounds with lanthanides in lower oxidation states exist.

Lanthanide dichlorides

Divalent chlorides are formed by

neodymium Neodymium is a chemical element with the symbol Nd and atomic number 60. It is the fourth member of the lanthanide series and is considered to be one of the rare-earth metals. It is a hard, slightly malleable, silvery metal that quickly tarnishes i ...

, samarium,

europium Europium is a chemical element with the symbol Eu and atomic number 63. Europium is the most reactive lanthanide by far, having to be stored under an inert fluid to protect it from atmospheric oxygen or moisture. Europium is also the softest lanth ...

dysprosium Dysprosium is the chemical element with the symbol Dy and atomic number 66. It is a rare-earth element in the lanthanide series with a metallic silver luster. Dysprosium is never found in nature as a free element, though, like other lanthanides, it ...

, thulium and ytterbium. They can be prepared by reducing the trivalent chloride with lithium metal/naphthalene in

tetrahydrofuran Tetrahydrofuran (THF), or oxolane, is an organic compound with the formula (CH2)4O. The compound is classified as heterocyclic compound, specifically a cyclic ether. It is a colorless, water-miscible organic liquid with low viscosity. It is ma ...

: : LnCl₃ + Li → LnCl₂ + LiCl (Ln=Nd,Sm,Eu) Reducing the chloride with the metal or

hydrogen Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic, an ...

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 Hydrochloric acid, also known as muriatic acid, is an aqueous solution of hydrogen chloride. It is a colorless solution with a distinctive pungent smell. It is classified as a strong acid Acid strength is the tendency of an acid, symbol ...

. They are produced commercially by

carbothermic reaction Carbothermic reactions involve the reduction of substances, often metal oxides (O^2-), using carbon as the reducing agent. These chemical reactions are usually conducted at temperatures of several hundred degrees Celsius. Such processes are applie ...

of the oxide. To produce the anhydrous forms of these trichlorides, the

ammonium chloride route Lanthanide trichlorides are a family of inorganic compound with the formula Ln Cl3, where Ln stands for a lanthanide metal. The trichlorides are standard reagents in applied and academic chemistry of the lanthanides. They exist as anhydrous solids ...

is taken. The anhydrous lanthanide trichlorides have high melting points and are generally pale colored.

References

{{Lanthanide halides Lanthanide compounds Chlorides Lanthanide halides

Lanthanide dichlorides

Lanthanide trichlorides

See also

References