Hydrothermal Synthesis and Structure of Neptunium(V) Oxide
- Department of Civil Engineering and Geological Sciences, University of Notre Dame, 156 Fitzpatrick Hall, Notre Dame, IN, 46556 (United States)
- Chemistry Division, Argonne National Laboratory, Argonne, IL, 60439 (United States)
Single crystals of Np{sub 2}O{sub 5} have been synthesized by low-temperature hydrothermal reaction of a (NpO{sub 2}){sup +} stock solution with natural calcite crystals. The structure of Np{sub 2}O{sub 5} was solved by direct methods and refined on the basis of F{sup 2} for all unique data collected on a Bruker X-ray diffractometer equipped with an APEX II CCD detector. Np{sub 2}O{sub 5} is monoclinic, space group P2/c, with a = 8.168(2) A, b = 6.584(1) A, c = 9.3130(2) A, {beta} = 116.01(1) deg., V = 449.8(2) A{sup 3}, and Z = 1. The structure contains chains of edge-sharing neptunyl pentagonal bi-pyramids linked into sheets through cation-cation interactions with distorted neptunyl square bi-pyramids. Additional cation-cation interactions connect the sheets into a three-dimensional framework. The formation of Np{sub 2}O{sub 5} on the surface of calcite crystals has important implications for the precipitation of isolated neptunyl phases in natural aqueous systems. (authors)
- Research Organization:
- Materials Research Society, 506 Keystone Drive, Warrendale, PA, 15086-7573 (United States)
- OSTI ID:
- 21062432
- Resource Relation:
- Conference: Symposium on Scientific Basis for Nuclear Waste Management, Boston - Massachusetts (United States), 27 Nov - 1 Dec 2006; Other Information: Country of input: France; 25 refs; Related Information: In: Proceedings of the symposium on Scientific Basis for Nuclear Waste Management XXX, by Dunn, Darrell [ed. Southwest Research Inst., San Antonio, Texas (United States)]; Poinssot, Christophe [ed. CEA-Saclay, 91191 Gif-sur-Yvette cedex (France)]; Begg, Bruce [ed. Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia)], v. 985, 663 pages.
- Country of Publication:
- United States
- Language:
- English
Similar Records
Crystal structure of complex neptunium(V) molybdate Na{sub 2}[(NpO{sub 2}){sub 2}(MoO{sub 4}){sub 2}H{sub 2}O] {center_dot} H{sub 2}O
Synthesis, structure determination, and infrared spectroscopy of (NpO{sub 2}){sub 2}(SO{sub 4})(H{sub 2}O){sub 4}: Prevalence of cation-cation interactions and cationic nets in neptunyl sulfate compounds