Raman spectroscopic study of the uranyl carbonate mineral voglite

Abstract

Raman spectroscopy complimented with infrared spectroscopy has been used to study the uranyl carbonate mineral voglite. The mineral has the formula Ca2Cu2+[(UO2)(CO3)3](CO3).6H2O and bands attributed to these vibrating units are readily identified in the Raman spectrum. Symmetric stretching modes at 836 and 1094 cm-1 are assigned to v1 (UO2)2+, and v1 (CO3)2- units. The v3 antisymmetric stretching modes of (UO2)2+ are not observed in the Raman spectrum but may be readily observed in the infrared spectrum at 898 cm-1. The v3 antisymmetric stretching mode of (CO3)2- is observed in the Raman spectrum at 1369 cm-1 as a low intensity band as is also the ν3 (CO3)2- infrared modes at 1362, 1425, 1509 and 1566 cm-1. No ν2 (CO3)2- Raman bending modes are observed for voglite. The Raman band at 749 cm-1 and the two infrared bands at 747 and 709 cm-1 are assigned to the ν4 (CO3)2- bending modes. U-O bond and O-H…O bond lengths in the structure of voglite were inferred from the infrared and Raman spectra.