Thorium(IV) chloride describes a family of
inorganic compound
In chemistry, an inorganic compound is typically a chemical compound that lacks carbon–hydrogen bonds, that is, a compound that is not an organic compound. The study of inorganic compounds is a subfield of chemistry known as '' inorganic chemist ...
s with the formula ThCl
4(H
2O)
n. Both the anhydrous and tetrahydrate (n = 4) forms are known. They are hygroscopic, water-soluble white salts.
Structures
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
ThCl
4 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
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 ...
, 700 °C to 2600 °C, involving thorium oxides and carbon in a stream of chlorine gas:
:ThO
2 + 2C + 4Cl
2 → ThCl
4 + 2CO
The chlorination reaction can be effected with carbon tetrachloride:
:Th(C
2O
4)
2 + CCl
4 → ThCl
4 + 3CO + 3CO
2
In another two-step method, thorium metal reacts with
ammonium chloride:
:Th + 6NH
4Cl → (NH
4)
2ThCl
6 + 4NH
3 + 2H
2
The hexachloride salt is then heated at 350 °C under a high vacuum to produce ThCl
4.
Reactions
;Lewis base adducts
ThCl
4 reacts with
Lewis base
A Lewis acid (named for the American physical chemist Gilbert N. Lewis) is a chemical species that contains an empty orbital which is capable of accepting an electron pair from a Lewis base to form a Lewis adduct. A Lewis base, then, is any sp ...
s to give molecular adducts, such as ThCl
4(DME)
2 and ThCl
4(TMEDA)
2.
;Reduction to Th metal
Thorium(IV) chloride is an intermediate in the purification of thorium, which can be affected by:
#Reduction of ThCl
4 with alkali metals.
#Electrolysis of anhydrous thorium(IV) chloride in fused mixture of NaCl and KCl.
#Ca reduction of a mixture of ThCl
4 with anhydrous zinc chloride.
References
Chlorides
Actinide halides
Thorium compounds
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