Raman spectroscopic study of the uranyl mineral pseudojohannite Cu6.5[(UO2)4O4(SO4)2]2(OH)5·25H2O

Abstract

AbstractRaman spectra of pseudojohannite were studied and related to the structure of the mineral. Observed bands were assigned to the stretching and bending vibrations of (UO2)2+ and (SO4)2− units and of water molecules. The published formula of pseudojohannite is Cu6.5(UO2)8[O8](OH)5[(SO4)4]·25H2O. Raman bands at 805 and 810 cm−1 are assigned to (UO2)2+ stretching modes. The Raman bands at 1017 and 1100 cm−1 are assigned to the (SO4)2− symmetric and antisymmetric stretching vibrations. The three Raman bands at 423, 465 and 496 cm−1 are assigned to the (SO4)2−ν2 bending modes. The bands at 210 and 279 cm−1 are assigned to the doubly degenerate ν2 bending vibration of the (UO2)2+ units. UO bond lengths in uranyl and OH···O hydrogen bond lengths were calculated from the Raman and infrared spectra. Copyright © 2009 John Wiley & Sons, Ltd.