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Title: The (3+3) commensurately modulated structure of the uranyl silicate mineral swamboite-(Nd), Nd 0.333[(UO 2)(SiO 3OH)](H 2O) 2.41

Abstract

The uranyl mineral swamboite has been redefined to swamboite-(Nd) and its structure has been solved and refined as a commensurate structure in six-dimensional superspace. The structure is monoclinic, superspace group P2 1 /m( a1, b1, g1)00(- a1, b1, g1)00 ( a2,0, g2)0 s, cell parameters a=6.6560(3), b=6.9881(5), c=8.8059(6), c=11.3361(16) Å, β=102.591(5)°, modulation wave-vectors q1=1/3 1/3 0; q2 = -1/3 1/3 0; q3=1/2 0 1/2. The structure was refined from 8717 reflections to a final R=0.0610. The model includes modulation both of atomic positions and displacement parameters, as well as occupancy waves. The structure is based upon uranyl-silicate sheets of uranophane topology alternating with an interlayer of partly occupied Nd 3+ sites and H 2O molecules. The strong (3+3) dimensional modulation of the structure originates from the distribution of the Nd-dominated sites and further accommodation of the suitable geometry within the sheets and charge distribution within the structure. The separation distances between the corresponding occupied Nd sites are rationals of the super-cell vectors corresponding to the modulation vectors of the structure. The case of swamboite-(Nd) is the first example of a modulated structure within the oxysalts of U 6+.

Authors:
; ; ; ;
Publication Date:
Research Org.:
Univ. of Notre Dame, IN (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1541926
DOE Contract Number:  
FG02-07ER15880
Resource Type:
Journal Article
Journal Name:
Zeitschrift fuer Kristallographie. Crystalline Materials
Additional Journal Information:
Journal Volume: 233; Journal Issue: 3-4; Journal ID: ISSN 2194-4946
Publisher:
de Gruyter
Country of Publication:
United States
Language:
English
Subject:
Crystallography

Citation Formats

Plášil, Jakub, Petříček, Václav, Locock, Andrew J., Škoda, Radek, and Burns, Peter C. The (3+3) commensurately modulated structure of the uranyl silicate mineral swamboite-(Nd), Nd0.333[(UO2)(SiO3OH)](H2O)2.41. United States: N. p., 2018. Web. doi:10.1515/zkri-2017-2119.
Plášil, Jakub, Petříček, Václav, Locock, Andrew J., Škoda, Radek, & Burns, Peter C. The (3+3) commensurately modulated structure of the uranyl silicate mineral swamboite-(Nd), Nd0.333[(UO2)(SiO3OH)](H2O)2.41. United States. doi:10.1515/zkri-2017-2119.
Plášil, Jakub, Petříček, Václav, Locock, Andrew J., Škoda, Radek, and Burns, Peter C. Wed . "The (3+3) commensurately modulated structure of the uranyl silicate mineral swamboite-(Nd), Nd0.333[(UO2)(SiO3OH)](H2O)2.41". United States. doi:10.1515/zkri-2017-2119.
@article{osti_1541926,
title = {The (3+3) commensurately modulated structure of the uranyl silicate mineral swamboite-(Nd), Nd0.333[(UO2)(SiO3OH)](H2O)2.41},
author = {Plášil, Jakub and Petříček, Václav and Locock, Andrew J. and Škoda, Radek and Burns, Peter C.},
abstractNote = {The uranyl mineral swamboite has been redefined to swamboite-(Nd) and its structure has been solved and refined as a commensurate structure in six-dimensional superspace. The structure is monoclinic, superspace group P21/m(a1,b1,g1)00(-a1,b1,g1)00 (a2,0,g2)0s, cell parameters a=6.6560(3), b=6.9881(5), c=8.8059(6), c=11.3361(16) Å, β=102.591(5)°, modulation wave-vectors q1=1/3 1/3 0; q2 = -1/3 1/3 0; q3=1/2 0 1/2. The structure was refined from 8717 reflections to a finalR=0.0610. The model includes modulation both of atomic positions and displacement parameters, as well as occupancy waves. The structure is based upon uranyl-silicate sheets of uranophane topology alternating with an interlayer of partly occupied Nd3+ sites and H2O molecules. The strong (3+3) dimensional modulation of the structure originates from the distribution of the Nd-dominated sites and further accommodation of the suitable geometry within the sheets and charge distribution within the structure. The separation distances between the corresponding occupied Nd sites are rationals of the super-cell vectors corresponding to the modulation vectors of the structure. The case of swamboite-(Nd) is the first example of a modulated structure within the oxysalts of U6+.},
doi = {10.1515/zkri-2017-2119},
journal = {Zeitschrift fuer Kristallographie. Crystalline Materials},
issn = {2194-4946},
number = 3-4,
volume = 233,
place = {United States},
year = {2018},
month = {3}
}