Infrared spectra of liebigite, andersonite, voglite and schroeckingerite

Infrared spectra of mineral possessing layer structure - liebigite, Ca2[UO2(CO3)3].(8-11) H2O, schroeckingerite, NaCa3[UO2(CO3)3]SO4F.10 H2O, voglite, Ca2Cu[UO2(CO3)4].6 H2O (?), and synthetic andersonite, Na2Ca[UO2(CO3)3].6 H2O - were measured and interpreted and compared with the published infrared spectra of ammonium, potassium, rubidium, and cesium dioxo-tricarbonatouranates(VI). From the analysis of the infrared spectra it follows - in accordance with the results of X-ray diffraction analysis - that in the dioxo-tricarbonatouranate(VI) complex anion, [UO2(CO3)3]4-, forming hexagonal bipyramid, three bidentately bonded carbonate groups are present in the equatorial plane (in liebigite and andersonite and apparently also in schroeckingerite and voglite). The coordinations of the SO42- and F- ions in schroeckingerite and of the fourth carbonate group (?) in voglite have not been elucidated.