Polarized IR and Raman spectra of (H2O)n clusters (n = 2–5) in the c-channels of apatite single crystals

Abstract

The infrared (IR) and Raman spectra of three samples of fluorapatite single crystals and carbonate fluorapatite single crystal in the region of 7000–400 cm–1 were studied. It has been shown that isomorphic substitution of the Ca2+ cation and the PO43- anion leads to an increase in the size of the c-channels in the apatite crystal, which is accompanied by the formation of water clusters of the (H2O) n and H3O+ · (H2O) n (n = 2–5) types as a result of the diffusion processes in these local sections of the c-channels.