Thorium(IV) chloride
{{chembox
| Verifiedfields = changed
| Watchedfields = changed
| verifiedrevid = 429359668
| Name = Thorium(IV) chloride
| ImageFile = ThCl4.png
| ImageName = Thorium(IV) chloride structure
| OtherNames =
|Section1={{Chembox Identifiers
| CASNo_Ref = {{cascite|correct|??}}
| CASNo = 10026-08-1
| ChemSpiderID = 59594
| EINECS = 233-056-1
| RTECS = XO6475000
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = 24Q3L637MM
| PubChem = 66209
| StdInChI = 1S/4ClH.Th/h4*1H;/q;;;;+4/p-4
| StdInChIKey = WEQHQGJDZLDFID-UHFFFAOYSA-J
| SMILES = Cl[Th](Cl)(Cl)Cl
}}
|Section2={{Chembox Properties
| Formula = ThCl4
| MolarMass = 373.849 g/mol
| Appearance = white needles
hygroscopic
| Density = 4.59 g/cm3, solid
| MeltingPtC = 770
| BoilingPtC = 921
}}
|Section3={{Chembox Structure
| CrystalStruct = tetragonal
}}
|Section7={{Chembox Hazards
| LD50 = 332 mg/kg intraperitoneal mouse
}}
}}
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 salts.
Structures
image:Kristallstruktur Uran(IV)-fluorid.png
The structure of thorium(IV) chloride features 8-coordinate Th centers with doubly bridging chloride ligands.{{cite journal |doi=10.1016/0022-5088(74)90224-0|title=Crystal Structures of ThCl4 Polymorphs|year=1974|last1=Mason|first1=J. T.|last2=Jha|first2=M. C.|last3=Chiotti|first3=P.|journal=Journal of the Less Common Metals|volume=34|pages=143–151}}
Synthesis
ThCl4 was an intermediate in the original isolation of thorium metal by Jons Jacob Berzelius.{{Cite journal|last=Weeks|first=Mary Elvira|date=1932-07-01|title=The Discovery of the Elements. XI. Some Elements Isolated with the Aid of Potassium and Sodium: Zirconium, Titanium, Cerium, and Thorium|journal=Journal of Chemical Education|volume=9|issue=7|pages=1231|doi=10.1021/ed009p1231|bibcode=1932JChEd...9.1231W|issn=0021-9584}}
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 + 2{{nbsp}}C + 4{{nbsp}}Cl2 → ThCl4 + 2{{nbsp}}CO
The chlorination reaction can be effected with carbon tetrachloride:{{Cite book|title=Handbook Of Preparative Inorganic Chemistry|last=Brauer|first=Georg|publisher=Academic Press|year=1963|location=New York}}{{Cite journal|last1=Gutierrez|first1=R. L.|last2=Herbst|first2=R. J.|date=October 1979|title=Preliminary Fabrication Studies of Alternative LMFBR Carbide Fuels|url=http://www.osti.gov/scitech/servlets/purl/5688597-2bGijb/|journal=Los Alamos Scientific Laboratory|doi=10.2172/5688597 }}
:Th(C2O4)2 + CCl4 → ThCl4 + 3{{nbsp}}CO + 3{{nbsp}}CO2
In another two-step method, thorium metal reacts with ammonium chloride:
:Th + 6{{nbsp}}NH4Cl → (NH4)2ThCl6 + 4{{nbsp}}NH3 + 2{{nbsp}}H2
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.{{Cite journal|last1=Cantat|first1=Thibault|last2=Scott|first2=Brian L.|last3=Kiplinger|first3=Jaqueline L.|date=2010-01-25|title=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|journal=Chemical Communications|language=en|volume=46|issue=6|pages=919–21|doi=10.1039/b923558b|pmid=20107650|issn=1364-548X|url=https://zenodo.org/record/1229998}}
;Reduction to Th metal
Thorium(IV) chloride is an intermediate in the purification of thorium, which can be affected by:
- Reduction of ThCl4 with alkali metals.
- Electrolysis of anhydrous thorium(IV) chloride in fused mixture of NaCl and KCl.
- Ca reduction of a mixture of ThCl4 with anhydrous zinc chloride.{{Cite web|url=http://periodic.lanl.gov/90.shtml|title=Periodic Table of Elements: Los Alamos National Laboratory|website=periodic.lanl.gov|access-date=2016-04-29}}
References
{{reflist}}
{{Thorium compounds}}
{{Chlorides}}
{{Actinide halides}}