Uranyl Peroxides

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Uranyl Peroxides
Ginger Sigmon
Dr. Peter Burns Karrie-ann Hughes
kubatko University of Notre Dame Summer 2004 REu
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• IntroDuction
• Background
• Synthesis
• Results
• Acknowledgments

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Remediation
Uranium mill tailings
Uranium
Alteration of spent nuclear fuel
Storage of high-level nuclear waste
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WHY PEROXIDES ? Thermodynamic Data
UO3(H2O)0.8 (xl) 2.2H2O (l) H2O2 (l)
(UO2)O2(H2O)4 (xl) ?Hr -58.2 4.3 kJ mol-1
Dehydrated schoepite
uranyl peroxide
studtite
studtite (UO2)O2(H2O)4
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• Synthesis
• Uranyl nitrate peroxide ? Crystals
• 2M or 4M bases (LiOH, NaOH, KOH, CsOH, RbOH, and
  NH4OH)
• 2M uranyl nitrate solution
• 30 peroxide solution
• 2M or 4M monovalent cation/anion solutions
• Organics

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• Monovalent Cation/Anion solns used
• (Li, Na, K, Cs, Rb, NH4)NO3
• K(Cl, Br, I, CrO4, Cr2O7, HCO3, IO3)
• Na2(MoO4, Cr2O7, CO3)

Organics used (a) Triethylamine (b)
Tartaric Acid (c) Oxalic Acid (d)
Dabco (e) diethylamine (f) ethylene
diamine (g) n-octylamine (h) piperazine
(a)
(b)
(c)
(d)
(e)
(f)
(g)
(h)
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• Results
• - Many experiments, many crystals
• - Some did not contain (UO2)2
• Others were known peroxide structures
• Then

Known Na structure
K2Cr2O7 crystals (didnt contain any U)
(K,Rb)OH
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back to the organic incorporation
- Tartaric acid added to a KOH synthesis
Uranium Crystal
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• Reflections
• CCD XRD
• (Charge Coupled Device X-ray Diffraction)

• These crystals are non-stable in air
• 120o K low temperature

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• Matrix very large volume
• Peak patterns proved single crystal
• Whats going on !?!

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318 total structures
(A)
(B)
(C)
(D)
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16
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58
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• 30s sphere on the CCD - XRD
• 5 and 6 member rings
• Polyhedra have 3 peroxide bonds
• 28 U polyhedra

G sphere
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• Sphere found earlier this year

G sphere
28 U
Large sphere
32 U
4, 5, and 6 member rings
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• Argonne National Labs
• Neptunium sphere ???

Actinide Facility
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• Argonne National Labs
• Neptunium small sphere
• 4 and 6 member rings
• Half occupied site at center

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• Future Work
• Continue running experiments
• U and Np based
• Do spheres exist in other actinides ?
• Applications of the spheres

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Np
Neptunium
237
92
U
Uranium
238.02891
 94
Pu
Plutonium
244

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• Acknowledgements
• Thank you to
• Dr. Peter Burns
• Karrie-Ann Hughes Kubatko
• Everyone in the Lab
• University of Notre Dame EMSI/CEGS