A vibrational spectroscopic study of the phosphate mineral churchite (REE)(PO4) 2H2O.

Abstract

Vibrational spectroscopy has been used to study the rare earth mineral churchite of formula (REE)(PO4)- _2H2O. The mineral contains a range of rare earth metals including yttrium depending on the locality. The Raman spectra of churchite-(REE) are characterized by an intense sharp band at 984 cm_1 assigned to the m1 ðPO3_ 4 Þ symmetric stretching mode. A lower intensity band observed at around 1067 cm_1 is attributed to the m3 ðPO3_ 4 Þ antisymmetric stretching mode. The ðPO3_ 4 Þ bending modes are observed at 497 cm_1 (m2) and 565 cm_1(m4). Raman bands at 649 and 681 cm_1 are assigned to water librational modes. Vibrational spectroscopy enables aspects of the structure of churchite to be ascertained.