Raman spectroscopic study of the uranyl carbonate mineral zellerite

Abstract

Raman and infrared spectra of the uranyl mineral zellerite, Ca[(UO2)(CO3)2(H2O)2].3H2O, were measured and tentatively interpreted. U-O bond in uranyl and O-H…O hydrogen bonds were calculated from the vibrational spectra. The presence of structurally nonequivalent water molecules in the crystal structure of zellerite was inferred. Proposed chemical formula of zellerite is supported.
Raman bands at 3514, 3375 and 2945 cm-1 and broad infrared bands at 3513, 3396 and 3326 cm-1 are related to the vOH stretching vibrations of hydrogen bopnded water molecules. Observed wavenumbers of these vibrations prove that in fact hydrogen bonds participate in the crystal structure of zellerite. The presence of two bands at 1618 and 1681 cm-1 proves structurally distinct and nonequivalent water molecules in the crystal structure of zellerite.