Hydrothermal Synthesis and Structure of Neptunium(V) Oxide

Tori Z Forbes; Peter C Burns; L Soderholm; S Skanthakumar

doi:10.1557/PROC-985-0985-NN12-02

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Hydrothermal Synthesis and Structure of Neptunium(V) Oxide

Journal article

Peer reviewed

Hydrothermal Synthesis and Structure of Neptunium(V) Oxide

Tori Z Forbes, Peter C Burns, L Soderholm and S Skanthakumar

MRS proceedings, Vol.985(1), 1202

07/01/2007

DOI: 10.1557/PROC-985-0985-NN12-02

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Abstract

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)

Materials Science

Precipitation

CALCITE

CATIONS

HYDROTHERMAL SYNTHESIS

INTERACTIONS

MONOCLINIC LATTICES

MONOCRYSTALS

NEPTUNIUM OXIDES

SPACE GROUPS

SURFACES

X-RAY DIFFRACTOMETERS

Details

Title: Subtitle: Hydrothermal Synthesis and Structure of Neptunium(V) Oxide
Creators: Tori Z Forbes - University of Iowa, Chemistry
Peter C Burns
L Soderholm - 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)
S Skanthakumar - Chemistry Division, Argonne National Laboratory, Argonne, IL, 60439 (United States)
Resource Type: Journal article
Publication Details: MRS proceedings, Vol.985(1), 1202
Publisher: Materials Research Society - MRS, Warrendale (United States)
DOI: 10.1557/PROC-985-0985-NN12-02
ISSN: 0272-9172
eISSN: 1946-4274
Language: English
Date published: 07/01/2007
Academic Unit: Civil and Environmental Engineering; Core Research Facilities; Chemistry
Record Identifier: 9984217460302771

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