Use of the Far Infrared Spectroscopy for NaCl and KCl Minerals Characterization—A Case Study of Halides from Kłodawa in Poland

The paper presents research on chloride minerals of natural origin from Kłodawa (Poland), i.e., colorless, blue and purple halite as well colorless sylvite. Selected samples were studied by chemical analysis (ICP-OES, ICP-MS, titration methods) crystallographic measurements. Then, for the tested halides, was carried out using far-infrared spectroscopy. Spectroscopic studies confirmed simple way distinguishing NaCl KCl spectroscopy, known in literature. novelty is that article first time experimental far infrared spectra halite. It observed (178 cm−1) (176 halites have strongest band slightly shifted towards higher wavenumbers compared to (174 cm−1). As part work, crystal structure models sodium potassium calculated density functional theory (with B3LYP 6-31G* basis set, 125-atom model). proposed approach can be used not only a powerful method differentiating minerals, but it also help with understanding different defects lattices naturally occurring halides crystals other minerals.