Raman and infrared spectroscopic studies of phurcalite from Red Canyon, Utah, U.S.A. - implications for the molecular structure.

Abstract

Raman and infrared spectra of the uranyl mineral phurcalite, Ca2(UO2)3O2(PO4)2_7H2O, from Red Canyon, Utah, USA, were studied and tentatively interpreted. Observed bands were assigned to the stretching and bending vibrations of (UO2)2+ and (PO4)3_ units and to the stretching and bending vibrations and libration modes of water molecules. Approximate lengths of U–O in (UO2)2+ and O–H_ _ _O hydrogen bond lengths were inferred from observed stretching vibrations. The presence of structurally nonequivalent U6+ and P5+ was inferred from the number of corresponding stretching bands of (UO2)2+ and (PO4)3_ units observed in the Raman and infrared spectra.