Molecular structure of the uranyl mineral andersonite-a Raman spectroscopic study

Frost, Ray L. and Carmody, Onuma and Erickson, Kristy L. and Weier, Matt L. and Cejka, Jiri (2004) Molecular structure of the uranyl mineral andersonite-a Raman spectroscopic study. Journal of Molecular Structure, 703(1-3). pp. 47-54.

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DOI : 10.1016/j.molstruc.2004.06.001

Abstract

The molecular structure of the mineral andersonite, a uranyl tricarbonates, has been studied by Raman microscopy at 298 and 77 K and ATR infrared spectroscopy. Raman bands are observed at 3558, 3510 and 3415 cm-1 and infrared bands at 3559, 3502, 3388, 3270 and 3120 cm-1 enabling estimates of the hydrogen bond distances of 2.98, 2.91, 2.80, 2.77, 2.707 and 2.701 Å to be estimated. The wide range of values shows the water molecules are not equivalent in the structure of andersonite. Two well resolved Raman bands at 1092 and 1080 cm-1 assigned to the ν1 symmetric stretching modes of the (CO3)2- units prove the existence of two non-equivalent carbonate units. A single peak at 832 cm-1 resolvable into two bands at 833 and 831 cm-1 is attributed to the overlap of the symmetric stretching modes of the (UO2)2+ units and the ν2 bending modes of the (CO3)2- units. The ν4 in-plane bending region is characterised by three Raman bands at 745, 726 and 698 cm-1 confirming the loss of symmetry of the carbonate anion and the non-equivalence of the carbonate units. Raman spectroscopy at 298 and 77 K assists in the assignation of bands to the structure of andersonite.

ID Code:	818
Item Type:	Journal Article
Additional Information :	Note: Co-author J.Cejka is affiliated with National Museum, Václavské náměstí 68, CZ-115 79 Praha 1, Czech Republic.
Keywords :	andersonite, liebigite, uranyl carbonate, dehydroxylation, dehydration, infrared and Raman spectroscopy
ISSN:	0022-2860
Subjects:	Australian and New Zealand Standard Research Classification > CHEMICAL SCIENCE (030000) > INORGANIC CHEMISTRY (030200)
Divisions:	QUT Faculties and Divisions > Faculty of Science
Copyright Owner :	Copyright 2004 Elsevier
Copyright Statement :	Reproduced in accordance with the copyright policy of the publisher: This journal is available online.
Deposited On:	14 Mar 2005
Last Modified:	03 Dec 2008 12:09

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