Thorium(IV) chloride

Structures

thumb|left|162px|Alternative view of the structure of solid ThCl4. The structure of thorium(IV) chloride features 8-coordinate Th centers with doubly bridging chloride ligands.

Synthesis

ThCl4 was an intermediate in the original isolation of thorium metal by Jons Jacob Berzelius.

Thorium(IV) chloride can be produced in a variety of ways. One method is a carbothermic reaction, 700 °C to 2600 °C, involving thorium oxides and carbon in a stream of chlorine gas: :ThO2 + 2C + 4Cl2 → ThCl4 + 2CO

The chlorination reaction can be effected with carbon tetrachloride: :Th(C2O4)2 + CCl4 → ThCl4 + 3CO + 3CO2

In another two-step method, thorium metal reacts with ammonium chloride: :Th + 6NH4Cl → (NH4)2ThCl6 + 4NH3 + 2H2 The hexachloride salt is then heated at 350 °C under a high vacuum to produce ThCl4.

Reactions

;Lewis base adducts ThCl4 reacts with Lewis bases to give molecular adducts, such as ThCl4(DME)2 and ThCl4(TMEDA)2.

;Reduction to Th metal Thorium(IV) chloride is an intermediate in the purification of thorium, which can be affected by:

1. Reduction of ThCl4 with alkali metals.
2. Electrolysis of anhydrous thorium(IV) chloride in fused mixture of NaCl and KCl.
3. Ca reduction of a mixture of ThCl4 with anhydrous zinc chloride.

References

References

1. (1974). "Crystal Structures of ThCl₄ Polymorphs". Journal of the Less Common Metals.
2. Weeks, Mary Elvira. (1932-07-01). "The Discovery of the Elements. XI. Some Elements Isolated with the Aid of Potassium and Sodium: Zirconium, Titanium, Cerium, and Thorium". Journal of Chemical Education.
3. Brauer, Georg. (1963). "Handbook Of Preparative Inorganic Chemistry". Academic Press.
4. (October 1979). "Preliminary Fabrication Studies of Alternative LMFBR Carbide Fuels". Los Alamos Scientific Laboratory.
5. (2010-01-25). "Convenient Access to the Anhydrous Thorium Tetrachloride Complexes ThCl₄(DME)₂, ThCl₄(1,4-dioxane)₂ and ThCl₄(THF)_3.5 using Commercially Available and Inexpensive Starting Materials". Chemical Communications.
6. "Periodic Table of Elements: Los Alamos National Laboratory".