Raman scattering and X-ray powder diffraction studies of hydrate layered perovskites: dirubidium aquapentafluoromanganate(III) and dipotassium aquapentafluoroferrate(III)

The structural and vibrational properties of above mentioned crystals were determined using X-ray powder diffraction and Raman scattering experiments. At room temperature hydrate layered perovskites: Rb2MnF5·H2O and K2FeF5·H2O exhibit orthorhombic—Cmcm (D2h17) and monoclinic—C2/c (C2h6) symmetry. Their structure is built up of MnF6 or FeF5·H2O octahedra forming trans-linked zig–zag chains or hydrogen bonded zig–zag chains along the major crystallographic direction [0 0 1], respectively. To confirm crystal structures and to describe lattice dynamics of these compounds the vibrational normal modes (in Γ point of first Brillouin zone) were calculated on the base of the group theory analysis and compared with the spectra obtained from Raman scattering experiments. A relatively good reliability was obtained for both X-ray powder diffraction and Raman scattering.