Uranyl chloride


Uranyl chloride refers to inorganic compounds with the formula UO2Cl2(H2O)n where n = 0, 1, or 3. These are yellow-colored solids.

Uranyl chloride
Uranyl chloride
IUPAC name
Other names
Uranium(VI), dichlorodioxy
  • 7791-26-6 checkY
3D model (JSmol)
  • Interactive image
  • hydrate: Interactive image
  • dihydrate: Interactive image
  • trihydrate: Interactive image
  • 21172763
ECHA InfoCard 100.029.315 Edit this at Wikidata
EC Number
  • 232-246-1
  • hydrate: 129671572
  • dihydrate: 129693634
  • trihydrate: 20376300
  • W2V47QQ17S checkY
  • DTXSID0064882 Edit this at Wikidata
  • hydrate: InChI=1S/2ClH.H2O.2O.U/h2*1H;1H2;;;/q;;;;;+2/p-2
  • dihydrate: InChI=1S/2ClH.2H2O.2O.U/h2*1H;2*1H2;;;/q;;;;;;+2/p-2
  • trihydrate: InChI=1S/2ClH.3H2O.2O.U/h2*1H;3*1H2;;;/q;;;;;;;+2/p-2
  • [Cl-].O=[U+2]=O.[Cl-]
  • hydrate: O.O=[U+2]=O.[Cl-].[Cl-]
  • dihydrate: O.O.O=[U+2]=O.[Cl-].[Cl-]
  • trihydrate: O.O.O.O=[U+2]=O.[Cl-].[Cl-]
Molar mass 340.90
Melting point Decomposes
Boiling point Decomposes
Solubility in other solvents 320 @ 18C
Safety data sheet (SDS) External MSDS
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Synthesis and structuresEdit

Structure of the molecular complex uranyl chloride, trihydrate (UO2Cl2(H2O)3). Color scheme: red = O, green = U, Cl.[1]

The hydrates are obtained by dissolving uranyl sulfate or uranyl acetate in hydrochloric acid followed by crystallization from concentrated solutions. Depending on the method of drying, one obtains the mono- or the trihydrate. The monohydrate is described as a yellow, sulfur-like powder. It is very hygroscopic.[2] The trihydrate is greenish-yellow. Both hydrates are fluorescent solids that are highly soluble in water.[3]

The anhydrous material can be obtained by the reaction of oxygen with uranium tetrachloride:

UCl4 + O2 → UO2Cl2 + Cl2

In terms of structures, all three of these compounds feature the uranyl center (trans-UO22+) bound to five additional ligands, which can include (bridging) chloride, water, or another uranyl oxygen.[4][5]


The aquo ligands can be replaced by a variety of donors, e.g. THF.[6]

Industrial importanceEdit

The company Indian Rare Earths Limited (IREL) has developed a process to extract uranium from the Western and Eastern coastal dune sands of India. After pre-processing with high-intensity magnetic separators and fine grinding, the mineral sands (known as monazite), are digested with caustic soda at about 120 °C (248 °F) and water. The hydroxide concentrate is further digested with concentrated hydrochloric acid to solubilise all hydroxides to form a feed solution composed of chlorides of uranium and other rare earth elements including thorium. The solution is subjected to liquid–liquid extraction with dual solvent systems to produce uranyl chloride and thorium oxalate. The crude uranyl chloride solution is subsequently refined to nuclear grade ammonium diuranate by a purification process involving precipitation and solvent extraction in a nitrate media.


  1. ^ Debets, P. C. (1968). "The structures of uranyl chloride and its hydrates". Acta Crystallographica Section B Structural Crystallography and Crystal Chemistry. 24 (3): 400–402. doi:10.1107/S056774086800244X.
  2. ^ Hefley, Jack D.; Mathews, Daniel M.; Amis, Edward S. (1963). "Uranyl Chloride 1-Hydrate". Inorganic Syntheses. Inorganic Syntheses. Vol. 7. pp. 146–148. doi:10.1002/9780470132388.ch41. ISBN 9780470132388.
  3. ^ F. Hein, S. Herzog (1963). "Uranyl Chloride". In G. Brauer (ed.). Handbook of Preparative Inorganic Chemistry, 2nd Ed. Vol. 2. NY, NY: Academic Press. p. 1439.
  4. ^ Taylor, J. C.; Wilson, P. W. (1973). "The Structure of Anhydrous Uranyl Chloride by Powder Neutron Diffraction". Acta Crystallographica Section B Structural Crystallography and Crystal Chemistry. 29 (5): 1073–1076. doi:10.1107/S0567740873003882.
  5. ^ Leary, Joseph A.; Suttle, John F. (1957). "Uranyl Chloride". Inorganic Syntheses. Inorganic Syntheses. Vol. 5. pp. 148–150. doi:10.1002/9780470132364.ch41. ISBN 9780470132364.
  6. ^ Wilkerson, Marianne P.; Burns, Carol J.; Paine, Robert T.; Scott, Brian L. (1999). "Synthesis and Crystal Structure of UO2Cl2(THF)3: A Simple Preparation of an Anhydrous Uranyl Reagent". Inorganic Chemistry. 38 (18): 4156–4158. doi:10.1021/ic990159g.
  • "Uranium". Encyclopædia Britannica. Vol. V27. 1911. p. 788.
  • Heyes, S.J. (1998). "Lanthanides & Actinides". Four Lectures in 2nd Year Inorganic Chemistry. Retrieved 22 November 2011.

External linksEdit

  • Settle, Frank. "Nuclear Chemistry and the Community". www.chemcases.com: General Chemistry Case Studies. Retrieved 22 November 2011.