Infrared spectra of rutherfordine and sharpite

Abstract

Infrared spectra (4 000-400 cm-1) of solid samples in KBr microdisks were measured and interpreted for uranyl carbonate minerals, viz. rutherfordine and sharpite, and synthetic phases in the system UO3-CO2-H2O; the mineral schoepite was studied for a comparison as well. The ν3 fundamental belonging to the UO22+ antisymmetric stretching vibrations in rutherfordine, UO2CO3.x H2O (0.2 > x ≥ 0), lies in the same range as for the hydrothermal phases (985 to 978 cm-1), whereas in the case of sharpite, UO2CO3.H2O or (UO2)6(CO3)5(OH)2.7 H2O or M1-x2+.(H3O)2x(UO2)6(CO3)5(OH)4.(6-2x) H2O, this vibration appears in the range where it is displayed by phases formed at normal temperature and pressure (954-953 and 914-913 cm-1). The IR spectrum of schoepite, UO3.2H2O, is published for the first time.