Structural dynamics of the layered CuCrS 2 is investigated for the first time by using the Raman scattering method in 78-295 K temperature range on the samples synthesized by different methods. The Raman and IR spectra of CuCrS 2 were simulated within the valence force field model with the LADY program. The results presented indicate that the lattice dynamics of CuCrS 2 depends strongly on the real microstructure and technology of the sample preparation. The anomalous splitting of the A 1 phonon mode might be due to presence of the α-and β-domains.

Raman scattering (RS) and infrared absorption (IR) of ammonium oxyfluoride crystals (NH 4 ) 3 WO 3 F 3 , (NH 4 ) 2 KWO 3 F 3 , and Cs 2 (NH 4 )WO 3 F 3 are compared. Conformation of the WO 3 F 3 octahedral groups has been established; anomalies have been found close to the transition temperatures in the internal vibrational regions of ammonium and WO 3 F 3 groups. The phase transition in (NH 4 ) 3 WO 3 F 3 is associated mostly with the ordering of octahedral groups and formation of W-O· · ·H-N hydrogen bonds.In (NH 4 ) 2 KWO 3 F 3 crystal, the transition is not related to the ordering processes; Cs 2 (NH 4 )WO 3 F 3 retains its disordered structure down to 10 K.

PACS 64.70. Kb, 78.30.Ly Raman scattering spectra of perovskite-like (NH 4 ) 3 WO 3 F 3 oxyfluoride are studied in the 70 -3600 cm -1 frequency range and the 93 -323 K temperature range including the transition point from orientationally disordered cubic phase into the lower symmetry one. Internal vibrations of ammonium ions and WO 3 F 3 octahedra have been found to exhibit transition anomalies. Analysis of measurements suggests that the transition under study is due mainly to the ordering of octahedra.