Raman Spectra of Vateritic Calcium Carbonate

Abstract

Abstract The Raman spectrum of polycrystalline vaterite is presented and compared to spectra of calcite and aragonite, the other two common CaCO3 polymorphs; Raman spectroscopy easily distinguishes between these three polymorphs. An important feature of the Raman spectrum of vaterite is splitting of both the ν1 and ν4 peaks. The splitting of the ν1 peak implies two distinct site symmetries for the CO3 −2 groups. A definitive crystal structure determination of vaterite is not yet available, but none of the three proposed structures for vaterite show such a feature.