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

Abstract

AbstractThe 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 (UO2)2+ and (SeO3)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 ν3 antisymmetric stretching mode of the (UO2)2+ (calculated UO bond length 1.808 Å). The band at 739 cm−1 was attributed to the ν3 antisymmetric stretching vibration of the (SeO3)2− units. The ν4 and the ν2 vibrational modes of the (SeO3)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.