Structural properties of Li2CO3-BaCO3 system derived from IR and Raman spectroscopy

In this work, we present the results of X-ray diffraction, IR and Raman spectroscopy measurements of Li2CO3-BaCO3 system in a whole range of composition. The investigated samples were prepared by melting and cooling down of the powder mixtures, and their properties were compared to the samples before melting (physical mixtures of powders). XRD results of fused carbonates showed that there are only two phases present: monoclinic Li2CO3 and orthorhombic BaCO3, and there is no shift in XRD reflex position. It indicates that barium and lithium carbonates do not form substitution solid solutions. However, the changes of some XRD reflex intensities were observed, suggesting the formation of diluted interstitial solid solutions or microstructure modification after melting. In order to determine the structure and microstructure modification after heat treatment the IR and Raman spectroscopic measurements were performed. The obtained results suggest the formation of additional amorphous phase in fused carbonates. (C) 2001 Elsevier Science B.V. All rights reserved.