Uranium(III) chloride, UCl₃, is a water soluble salt of uranium. UCl₃ is used mostly to reprocess spent nuclear fuel. Uranium(III) chloride is synthesized in various ways from uranium(IV) chloride; however, UCl₃ is less stable than UCl₄.

Preparation

There are two ways to synthesize uranium(III) chloride. The following processes describe how to produce uranium(III) chloride. (1) In a mixture of NaCl-KCl at 670–710 °C, add uranium tetrachloride with uranium metal. :3 UCl₄ + U → 4UCl₃ (2) Heat uranium(IV) chloride in hydrogen gas. :2 UCl₄ + H₂ → 2UCl₃ + 2

HCl HCL may refer to: Science and medicine * Hairy cell leukemia, an uncommon and slowly progressing B cell leukemia * Harvard Cyclotron Laboratory, from 1961 to 2002, a proton accelerator used for research and development * Hollow-cathode lamp, a spe ...

Properties

In solid uranium(III) chloride each uranium atom has nine chlorine atoms as near neighbours, at approximately the same distance, in a tricapped trigonal prismatic configuration. Uranium(III) chloride is a green crystalline solid at room temperature. UCl₃ melts at 837 °C and boils at 1657 °C. Uranium(III) chloride has a density of 5500 kg/m³ or 5.500 g/cm³. Its composition by weight: :Chlorine: 30.84% :Uranium: 69.16% Its formal oxidative states: :Chlorine: −1 :Uranium: +3 This salt is very soluble in water and is also very

hygroscopic Hygroscopy is the phenomenon of attracting and holding water molecules via either absorption or adsorption from the surrounding environment, which is usually at normal or room temperature. If water molecules become suspended among the substance ...

. UCl₃ is more stable in a solution of

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 ...

Uses

Reagent

Uranium(III) chloride is used in reactions with

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 ...

(THF) and sodium methylcyclopentadiene to prepare various uranium

metallocene A metallocene is a compound typically consisting of two cyclopentadienyl anions (, abbreviated Cp) bound to a metallic element, metal center (M) in the oxidation state II, with the resulting general formula Closely related to the metallocenes are ...

complexes.

Catalyst

Uranium(III) chloride is used as a catalyst during reactions between

lithium aluminium hydride Lithium aluminium hydride, commonly abbreviated to LAH, is an inorganic compound with the chemical formula Li Al H4. It is a white solid, discovered by Finholt, Bond and Schlesinger in 1947. This compound is used as a reducing agent in organic ...

(LiAlH₄) and olefins to produce alkyl aluminate compounds.

Molten form

The molten form of uranium(III) chloride is a typical compound in pyrochemical processes as it is important in the reprocessing of

spent nuclear fuel Spent nuclear fuel, occasionally called used nuclear fuel, is nuclear fuel that has been irradiated in a nuclear reactor (usually at a nuclear power plant). It is no longer useful in sustaining a nuclear reaction in an ordinary thermal reactor an ...

s.Okamoto, Y.; Madden, P.; Minato, K. J. Nucl. Mater. 2005, 344, 109–114. UCl₃ is usually the form that uranium takes as spent fuel in electrorefining processes.

Hydrates

There are three hydrates of uranium(III) chloride: #UCl₃^.2H₂O^.2CH₃CN #UCl₃^.6H₂O #UCl₃^.7H₂O Each are synthesized by the reduction of uranium(IV) chloride in methylcyanide (

acetonitrile Acetonitrile, often abbreviated MeCN (methyl cyanide), is the chemical compound with the formula and structure . This colourless liquid is the simplest organic nitrile (hydrogen cyanide is a simpler nitrile, but the cyanide anion is not clas ...

), with specific amounts of water and

propionic acid Propionic acid (, from the Greek words πρῶτος : ''prōtos'', meaning "first", and πίων : ''píōn'', meaning "fat"; also known as propanoic acid) is a naturally occurring carboxylic acid with chemical formula CH3CH2CO2H. It is a liq ...

Precautions

While there are no long-term data on the toxic effects thas UCl₃, it is important to minimize exposure to this compound when possible. Similar to other uranium compounds that are soluble, UCl₃ is likely absorbed into the blood through the alveolar pockets of the lungs within days of exposure. Exposure to uranium(III) chloride leads to toxicity of the renal system.Bertell, Rosalie. "Gulf War Veterans and Depleted Uranium." May 1999. Available: http://ccnr.org/du_hague.html

References

External links

Uranium(III) chloride information at Webelements
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{{Chlorides Uranium(III) compounds Chlorides Actinide halides