A Family of Layered Phosphates Crystallizing in a Rare Geometrical Isomer of the Phosphuranylite Topology: Synthesis, Characterization, and Computational Modeling of A4[(UO2)3O2(PO4)2] (A = Alkali Metal) Exhibiting Intralayer Ion Exchange
Journal Article
·
· Inorganic Chemistry
- Univ. of South Carolina, Columbia, SC (United States). The Center for Hierarchical Wasteform Materials
Single crystals of eight new layered uranyl phosphates were grown from alkali chloride fluxes: Cs1.4K2.6[(UO2)3O2(PO4)2], Cs0.7K3.3[(UO2)3O2(PO4)2], Rb1.4K2.6[(UO2)3O2(PO4)2], K4[(UO2)3O2(PO4)2], K2.9Na0.9Rb0.2[(UO2)3O2(PO4)2], K2.1Na0.7Rb1.2[(UO2)3O2(PO4)2], Cs1.7K4.3[(UO2)5O5(PO4)2], and Rb1.6K4.4[(UO2)5O5(PO4)2]. All structures crystallize in the monoclinic space group, P21/c and contain uranyl phosphate layers with alkali metals located between the layers for charge balance. Ion exchange experiments on Cs0.7K3.3[(UO2)3O2(PO4)2], Rb1.4K2.6[(UO2)3O2(PO4)2], and K4[(UO2)3O2(PO4)2] demonstrated that Cs and Rb cations cannot be exchanged for K cations; however, K cations can be readily exchanged for Na, Rb, and Cs. Enthalpies of formation were calculated from density functional theory (DFT) and volume-based thermodynamics (VBT) for all six structures. A value for the enthalpy of formation of the phosphuranylite sheet, [(UO2)3O2(PO4)2]4–, was derived using single-ion additive methods coupled with VBT. Finally, DFT and VBT calculations were used to justify results of the ion exchange experiments. Cs0.7K3.3[(UO2)3O2(PO4)2], Rb1.4K2.6[(UO2)3O2(PO4)2], and K4[(UO2)3O2(PO4)2] exhibit typical luminescence of the uranyl group.
- Research Organization:
- Energy Frontier Research Centers (EFRC), Washington D.C. (United States). Center for Hierarchical Waste Form Materials (CHWM)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
- Grant/Contract Number:
- SC0016574
- OSTI ID:
- 1470523
- Journal Information:
- Inorganic Chemistry, Journal Name: Inorganic Chemistry Journal Issue: 8 Vol. 57; ISSN 0020-1669
- Publisher:
- American Chemical Society (ACS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
Understanding the Stability of Salt-Inclusion Phases for Nuclear Waste-forms through Volume-based Thermodynamics
|
journal | October 2018 |
Flux crystal growth: a versatile technique to reveal the crystal chemistry of complex uranium oxides
|
journal | January 2019 |
Targeted crystal growth of uranium gallophosphates via the systematic exploration of the UF 4 –GaPO 4 –ACl (A = Cs, Rb) phase space
|
journal | January 2020 |
Similar Records
Crystal Growth and Structure Characterization of Three Layered Uranyl Phosphates and Their Relation to the Phosphuranylite Family
Observation of the Same New Sheet Topology in Both the Layered Uranyl Oxide-Phosphate Cs11[(UO2)12(PO4)3O13] and the Layered Uranyl Oxyfluoride-Phosphate Rb11[(UO2)12(PO4)3O12F2] Prepared by Flux Crystal Growth
Journal Article
·
Mon Dec 17 23:00:00 EST 2018
· Crystal Growth and Design
·
OSTI ID:1566487
Observation of the Same New Sheet Topology in Both the Layered Uranyl Oxide-Phosphate Cs11[(UO2)12(PO4)3O13] and the Layered Uranyl Oxyfluoride-Phosphate Rb11[(UO2)12(PO4)3O12F2] Prepared by Flux Crystal Growth
Journal Article
·
Tue Aug 20 20:00:00 EDT 2019
· Frontiers in Chemistry
·
OSTI ID:1564451