Raman spectroscopic study of the uranyl selenite mineral marthozite Cu[(UO₂)₃(SeO₃)₂O₂]·8H₂O

Abstract

Abstract The mineral marthozite, a uranyl selenite, has been characterised by Raman spectroscopy at 298 K. The bands at 812 and 797 cm −1 were assigned to the symmetric stretching modes of the (UO 2 ) 2+ and (SeO 3 ) 2− units, respectively. These values gave the calculated UO bond lengths in uranyl of 1.799 and/or 1.814 Å. Average UO bond length in uranyl is 1.795 Å, inferred from the X‐ray single crystal structure analysis of marthozite by Cooper and Hawthorne. The broad band at 869 cm −1 was assigned to the ν 3 antisymmetric stretching mode of the (UO 2 ) 2+ (calculated UO bond length 1.808 Å). The band at 739 cm −1 was attributed to the ν 3 antisymmetric stretching vibration of the (SeO 3 ) 2− units. The ν 4 and the ν 2 vibrational modes of the (SeO 3 ) 2− units were observed at 424 and 473 cm −1 . Bands observed at 257, and 199 and 139 cm −1 were assigned to OUO bending vibrations and lattice vibrations, respectively. OH···O hydrogen bond lengths were inferred using Libowiztky's empirical relation. The infrared spectrum of marthozite was studied for complementation. Copyright © 2008 John Wiley & Sons, Ltd.