Plutonium tetrachloride

Last updated
Plutonium tetrachloride
Names
IUPAC name
Plutonium(IV) chloride
Identifiers
3D model (JSmol)
  • InChI=1S/4ClH.Pu/h4*1H;/q;;;;+4/p-4
    Key: QNJPYBOCFFOTGM-UHFFFAOYSA-J
  • [Cl-].[Cl-].[Cl-].[Cl-].[Pu+4]
Properties
PuCl4
Molar mass 386 g·mol−1
Related compounds
Other anions
Plutonium tetrafluoride
Other cations
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Plutonium tetrachloride or plutonium(IV) chloride is an inorganic compound of plutonium and chlorine with the chemical formula PuCl4. While it is not known as a solid, gaseous PuCl4 is known. In addition, it is known to form several stable adducts. The dimethoxyethane adduct, PuCl4(DME)2, has been used as a precursor to other plutonium compounds.

Contents

Synthesis

The compound is formed when plutonium trichloride is put in a stream of chlorine: [1] : 1094 

2 PuCl3 + Cl2 → 2 PuCl4

Physical properties

The compound is not stable as a solid; however, it is known in the gas phase. When condensed, it forms plutonium(III) chloride and chlorine gas: [1] : 1094 

2 PuCl4 → 2 PuCl3 + Cl2

However, several stable adducts, such as with dimethoxyethane (PuCl4(DME)2) [2] or diphenylsulfoxide, [3] and ammoniates (solids incorporating ammonia), [4] are known. The diphenylsulfoxide adduct appears as a red solid. [3]

Complexes

With dimethoxyethane

Plutonium tetrachloride forms a stable adduct with dimethoxyethane (CH3OCH2CH2OCH3) with formula PuCl4(DME)2 (DME=dimethoxyethane). This compound can be prepared via evaporation of a hydrochloric acid solution containing plutonium(IV), adding the product to dimethoxyethane, and then adding trimethylsilyl chloride. [2] This adduct can be used to prepare other compounds. For example, when it is dissolved in tetrahydrofuran, it is partially reduced to form the mixed-valence complex [PuIIICl2(THF)5]+[PuIVCl5(THF)]−. (THF=tetrahydrofuran). [5] It has also been used to prepare the compound plutonium(IV) N-(tert-butyl)isobutyramide (Pu(ita)4, ita=N-(tert-butyl)isobutyramide) through reaction with potassium N-(tert-butyl)isobutyramide. Pu(ita)4 has been investigated in the production of oxidation state-pure plutonium(IV) oxide. [6]

The structure of the dimethoxyethane adduct of plutonium tetrachloride. Green represents chlorine atoms, red represents oxygen atoms, grey represents carbon atoms, white represents hydrogen atoms, and blue represents plutonium atoms. PuCl4(DME)2 structure.png
The structure of the dimethoxyethane adduct of plutonium tetrachloride. Green represents chlorine atoms, red represents oxygen atoms, grey represents carbon atoms, white represents hydrogen atoms, and blue represents plutonium atoms.

Other complexes

Plutonium tetrachloride also forms an adduct with diphenylsulfoxide (Ph2SO). This adduct has been prepared by boiling a solution consisting of plutonium(IV) dissolved in hydrochloric acid, suspending the residue in acetonitrile, and adding to it an acetonitrile solution of diphenylsulfoxide. The resulting product has the formula PuCl4(Ph2SO)3, and is a rare example of plutonium in its +4 oxidation state with a coordination number of 7 (forming 7 bonds). [3]

When the related compound dicaesium hexachloroplutonate is reacted with liquid ammonia at low temperatures, the ammoniate (solid incorporating ammonia). The initial product has composition PuCl4·~7–8NH3, which decomposes over a period of weeks to form PuCl4·5NH3. PuCl4·5NH3 is stable at room temperature. Both compounds are ammine complexes, meaning that the ammonia in them is bonded to the plutonium atoms. [4]

Uses

A mixture of uranium tetrachloride and plutonium tetrachloride can be used as fuel for nuclear reactors. [7]

Anionic derivatives

Even though binary plutonium(IV) chloride is not known as a solid, solid compounds derived from it, such as dicaesium hexachloroplutonate (Cs2PuCl6), are known. [1] : 1094  In this compound, the +4 oxidation state of plutonium is stabilized by complexing with caesium chloride. [8] : 149  It is made up of discrete hexachloroplutonate (PuCl2−6) ions. [1]

Diagram of the hexachloroplutonate ion. Green spheres represent chlorine atoms, and blue spheres represent plutonium atoms. Hexachloroplutonate 3D.png
Diagram of the hexachloroplutonate ion. Green spheres represent chlorine atoms, and blue spheres represent plutonium atoms.

References

  1. 1 2 3 4 Clark, David L.; Hecker, Siegfried S.; Jarvinen, Gordon D.; Neu, Mary P. (2011). "Plutonium". The Chemistry of the Actinide and Transactinide Elements (PDF). doi:10.1007/978-94-007-0211-0_7. ISBN   978-94-007-0211-0.
  2. 1 2 Reilly, Sean D.; Brown, Jessie L.; Scott, Brian L.; Gaunt, Andrew J. (2014). "Synthesis and characterization of NpCl4(DME)2 and PuCl4(DME)2 neutral transuranic An(iv) starting materials". Dalton Trans. 43 (4): 1498–1501. doi:10.1039/C3DT53058B. PMID   24285347.
  3. 1 2 3 Cary, Samantha K.; Boland, Kevin S.; Cross, Justin N.; Kozimor, Stosh A.; Scott, Brian L. (2017). "Advances in containment methods and plutonium recovery strategies that led to the structural characterization of plutonium(IV) tetrachloride tris-diphenylsulfoxide, PuCl4(OSPh2)3". Polyhedron. 126: 220–226. doi:10.1016/j.poly.2017.01.013. OSTI   1371670.
  4. 1 2 Cleveland, J. M.; Bryan, G. H.; Sironen, R. J. (1 January 1972). "Ammoniates of plutonium(III) and (IV) halides" . Inorganica Chimica Acta . 6: 54–58. doi:10.1016/S0020-1693(00)91758-4. ISSN   0020-1693 . Retrieved 27 September 2025.
  5. ↑ Pattenaude, Scott A.; Anderson, Nickolas H.; Bart, Suzanne C.; Gaunt, Andrew J.; Scott, Brian L. (2018). "Non-aqueous neptunium and plutonium redox behaviour in THF – access to a rare Np(III) synthetic precursor". Chemical Communications. 54 (48): 6113–6116. doi:10.1039/C8CC02611D. OSTI   1436357. PMID   29736543.
  6. ↑ Peterson, Appie; Kelly, Sheridon N.; Arino, Trevor; Gunther, S. Olivia; Ouellette, Erik T.; Wacker, Jennifer N.; Woods, Joshua J.; Teat, Simon J.; Lukens, Wayne W.; Arnold, John; Abergel, Rebecca J.; Minasian, Stefan G. (2024). "Formation of Fully Stoichiometric, Oxidation-State Pure Neptunium and Plutonium Dioxides from Molecular Precursors". Inorganic Chemistry. 63 (39): 18417–18428. doi:10.1021/acs.inorgchem.4c02099. PMC   11445724 . PMID   39284039.
  7. ↑ Liu, Chunyu; Luo, Run; Macián-Juan, Rafael (15 October 2021). "A New Uncertainty-Based Control Scheme of the Small Modular Dual Fluid Reactor and Its Optimization". Energies . 14 (20): 6708. doi: 10.3390/en14206708 . ISSN   1996-1073.
  8. ↑ Lemire, R. J. et al., Chemical Thermodynamics of Neptunium and Plutonium, Elsevier, Amsterdam, 2001.
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