Thorium(IV) chloride

Thorium(IV) chloride describes a family of inorganic compounds with the formula ThCl4(H2O)n. Both the anhydrous and tetrahydrate (n = 4) forms are known. They are hygroscopic, water-soluble white solids. 
Structures.
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, a carbothermic reaction, 700 °C to 2600 °C, involving thorium oxides and carbon in a stream of chlorine gas:
The chlorination reaction can be effected with carbon tetrachloride:
In another two-step method, thorium metal reacts with ammonium chloride:
The hexachloride salt is then heated at 350 °C under a high vacuum to produce ThCl4.
Reactions.
ThCl4 reacts with Lewis bases to give molecular adducts, such as ThCl4(DME)2 and ThCl4(TMEDA)2.
Thorium(IV) chloride is an intermediate in the purification of thorium, which can be effected by