Raman Spectra of Vateritic Calcium Carbonate

Gesa Behrens, Case Western Reserve University
Liisa T. Kuhn, Case Western Reserve University
Rick Ubic, Boise State University
Arthur H. Heuer, Case Western Reserve University

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.