Phase transformations in LnF3-(Ln, Zr)-ZrF4 systems, where Ln = Sm, Eu, Tm, Yb

Phase transformations in LnF(3)-(Ln, Zr)-ZrF4 systems (where Ln = Sm, Eu, Tm, Yb) in the temperature range 700-900 degrees C have been investigated by chemical and X-ray phase analyses, UV and IR spectroscopy. Synthesis conditions of nonstoichiometric samarium, europium, ytterbium and thulium fluorides, which are products of interaction between LnF(3) and Ln and original substances for the preparation of compounds such as LnZrF(6) are given. The crystal lattice of the fluorozirconates obtained is similar to the Yb27F64 superstructure. Thulium fluorozirconate (TmZrF6), whose structure is indexed as the Tm13F32-delta superstructure of hexagonal system, is an exception. For all compounds obtained, the lattice parameters have been calculated and the absorption bands of IR spectra have been interpreted. (C) 2009 Elsevier B.V. All rights reserved.