Mid- and far-infrared spectral links for calcium carbonate polymorphs

We compare mid- and far-infrared attenuated total reflectance spectra for calcite and aragonite, which are two polymorphs of calcium carbonate, CaCO₃, in order to demonstrate which spectral feature changes can be attributed to phase (crystal structure) differences. These comparisons, together with our recent studies of multi-phase carbonate-containing samples, help to lay the groundwork for distinguishing far-infrared spectral features that are related to crystallinity differences in calcium carbonates.