Fortes, AD;
(2015)
Crystal structures of spinel-type Na2MoO4 and Na2WO4 revisited using neutron powder diffraction.
Acta Crystallographica Section E
, 71
(Pt 6)
pp. 592-596.
10.1107/S2056989015008774.
Preview |
Text
wm5152.pdf Download (499kB) | Preview |
Abstract
Time-of-flight neutron powder diffraction data have been collected from Na2MoO4 and Na2WO4 to a resolution of sin (θ)/λ = 1.25 Å(-1), which is substanti-ally better than the previous analyses using Mo Kα X-rays, providing roughly triple the number of measured reflections with respect to the previous studies [Okada et al. (1974 ▶). Acta Cryst. B30, 1872-1873; Bramnik & Ehrenberg (2004 ▶). Z. Anorg. Allg. Chem. 630, 1336-1341]. The unit-cell parameters are in excellent agreement with literature data [Swanson et al. (1962 ▶). NBS Monograph No. 25, sect. 1, pp. 46-47] and the structural parameters for the molybdate agree very well with those of Bramnik & Ehrenberg (2004 ▶). However, the tungstate structure refinement of Okada et al. (1974 ▶) stands apart as being conspicuously inaccurate, giving significantly longer W-O distances, 1.819 (8) Å, and shorter Na-O distances, 2.378 (8) Å, than are reported here or in other simple tungstates. As such, this work represents an order-of-magnitude improvement in precision for sodium molybdate and an equally substantial improvement in both accuracy and precision for sodium tungstate. Both compounds adopt the spinel structure type. The Na(+) ions have site symmetry .-3m and are in octa-hedral coordination while the transition metal atoms have site symmetry -43m and are in tetra-hedral coordination.
| Type: | Article |
|---|---|
| Title: | Crystal structures of spinel-type Na2MoO4 and Na2WO4 revisited using neutron powder diffraction |
| Location: | England |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1107/S2056989015008774 |
| Publisher version: | http://dx.doi.org/10.1107/S2056989015008774 |
| Language: | English |
| Additional information: | This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited. |
| Keywords: | neutron powder diffraction, sodium molybdate, sodium tungstate |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Earth Sciences |
| URI: | https://discovery.ucl.ac.uk/id/eprint/1468469 |
Loading...
Loading...Loading...| 1. |  United States | 8 |
| 2. |  China | 2 |
| 3. |  Japan | 1 |
| 4. |  Germany | 1 |
Archive Staff Only
 |
View Item |
