Raman spectroscopic study of the uranyl mineral pseudojohannite Cu 6.5 [(UO 2 ) 4 O 4 (SO 4 ) 2 ] 2 (OH) 5 ·25H 2 O

Raman spectra of pseudojohannite were studied and related to the structure of the mineral. Observed bands were assigned to the stretching and bending vibrations of (UO 2 ) 2+ and (SO 4 ) 2− units and of water molecules. The published formula of pseudojohannite is Cu 6.5 (UO 2 ) 8 [O 8 ](OH) 5 [(SO 4 ) 4 ]·25H 2 O. Raman bands at 805 and 810 cm −1 are assigned to (UO 2 ) 2+ stretching modes. The Raman bands at 1017 and 1100 cm −1 are assigned to the (SO 4 ) 2− symmetric and antisymmetric stretching vibrations. The three Raman bands at 423, 465 and 496 cm −1 are assigned to the (SO 4 ) 2− ν 2 bending modes. The bands at 210 and 279 cm −1 are assigned to the doubly degenerate ν 2 bending vibration of the (UO 2 ) 2+ units. UO bond lengths in uranyl and OH···O hydrogen bond lengths were calculated from the Raman and infrared spectra. Copyright © 2009 John Wiley & Sons, Ltd.